linux/drivers/block/aoe/aoechr.c

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/* Copyright (c) 2007 Coraid, Inc. See COPYING for GPL terms. */
/*
* aoechr.c
* AoE character device driver
*/
#include <linux/hdreg.h>
#include <linux/blkdev.h>
#include <linux/completion.h>
aoe: handle multiple network paths to AoE device A remote AoE device is something can process ATA commands and is identified by an AoE shelf number and an AoE slot number. Such a device might have more than one network interface, and it might be reachable by more than one local network interface. This patch tracks the available network paths available to each AoE device, allowing them to be used more efficiently. Andrew Morton asked about the call to msleep_interruptible in the revalidate function. Yes, if a signal is pending, then msleep_interruptible will not return 0. That means we will not loop but will call aoenet_xmit with a NULL skb, which is a noop. If the system is too low on memory or the aoe driver is too low on frames, then the user can hit control-C to interrupt the attempt to do a revalidate. I have added a comment to the code summarizing that. Andrew Morton asked whether the allocation performed inside addtgt could use a more relaxed allocation like GFP_KERNEL, but addtgt is called when the aoedev lock has been locked with spin_lock_irqsave. It would be nice to allocate the memory under fewer restrictions, but targets are only added when the device is being discovered, and if the target can't be added right now, we can try again in a minute when then next AoE config query broadcast goes out. Andrew Morton pointed out that the "too many targets" message could be printed for failing GFP_ATOMIC allocations. The last patch in this series makes the messages more specific. Signed-off-by: Ed L. Cashin <ecashin@coraid.com> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 15:20:00 +03:00
#include <linux/delay.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 11:04:11 +03:00
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/skbuff.h>
#include <linux/export.h>
#include "aoe.h"
enum {
//MINOR_STAT = 1, (moved to sysfs)
MINOR_ERR = 2,
MINOR_DISCOVER,
MINOR_INTERFACES,
MINOR_REVALIDATE,
MINOR_FLUSH,
MSGSZ = 2048,
NMSG = 100, /* message backlog to retain */
};
struct aoe_chardev {
ulong minor;
char name[32];
};
enum { EMFL_VALID = 1 };
struct ErrMsg {
short flags;
short len;
char *msg;
};
static DEFINE_MUTEX(aoechr_mutex);
static struct ErrMsg emsgs[NMSG];
static int emsgs_head_idx, emsgs_tail_idx;
static struct completion emsgs_comp;
static spinlock_t emsgs_lock;
static int nblocked_emsgs_readers;
static struct class *aoe_class;
static struct aoe_chardev chardevs[] = {
{ MINOR_ERR, "err" },
{ MINOR_DISCOVER, "discover" },
{ MINOR_INTERFACES, "interfaces" },
{ MINOR_REVALIDATE, "revalidate" },
{ MINOR_FLUSH, "flush" },
};
static int
discover(void)
{
aoecmd_cfg(0xffff, 0xff);
return 0;
}
static int
interfaces(const char __user *str, size_t size)
{
if (set_aoe_iflist(str, size)) {
printk(KERN_ERR
"aoe: could not set interface list: too many interfaces\n");
return -EINVAL;
}
return 0;
}
static int
revalidate(const char __user *str, size_t size)
{
int major, minor, n;
ulong flags;
struct aoedev *d;
aoe: handle multiple network paths to AoE device A remote AoE device is something can process ATA commands and is identified by an AoE shelf number and an AoE slot number. Such a device might have more than one network interface, and it might be reachable by more than one local network interface. This patch tracks the available network paths available to each AoE device, allowing them to be used more efficiently. Andrew Morton asked about the call to msleep_interruptible in the revalidate function. Yes, if a signal is pending, then msleep_interruptible will not return 0. That means we will not loop but will call aoenet_xmit with a NULL skb, which is a noop. If the system is too low on memory or the aoe driver is too low on frames, then the user can hit control-C to interrupt the attempt to do a revalidate. I have added a comment to the code summarizing that. Andrew Morton asked whether the allocation performed inside addtgt could use a more relaxed allocation like GFP_KERNEL, but addtgt is called when the aoedev lock has been locked with spin_lock_irqsave. It would be nice to allocate the memory under fewer restrictions, but targets are only added when the device is being discovered, and if the target can't be added right now, we can try again in a minute when then next AoE config query broadcast goes out. Andrew Morton pointed out that the "too many targets" message could be printed for failing GFP_ATOMIC allocations. The last patch in this series makes the messages more specific. Signed-off-by: Ed L. Cashin <ecashin@coraid.com> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 15:20:00 +03:00
struct sk_buff *skb;
char buf[16];
if (size >= sizeof buf)
return -EINVAL;
buf[sizeof buf - 1] = '\0';
if (copy_from_user(buf, str, size))
return -EFAULT;
/* should be e%d.%d format */
n = sscanf(buf, "e%d.%d", &major, &minor);
if (n != 2) {
printk(KERN_ERR "aoe: invalid device specification\n");
return -EINVAL;
}
d = aoedev_by_aoeaddr(major, minor);
if (!d)
return -EINVAL;
spin_lock_irqsave(&d->lock, flags);
aoe: handle multiple network paths to AoE device A remote AoE device is something can process ATA commands and is identified by an AoE shelf number and an AoE slot number. Such a device might have more than one network interface, and it might be reachable by more than one local network interface. This patch tracks the available network paths available to each AoE device, allowing them to be used more efficiently. Andrew Morton asked about the call to msleep_interruptible in the revalidate function. Yes, if a signal is pending, then msleep_interruptible will not return 0. That means we will not loop but will call aoenet_xmit with a NULL skb, which is a noop. If the system is too low on memory or the aoe driver is too low on frames, then the user can hit control-C to interrupt the attempt to do a revalidate. I have added a comment to the code summarizing that. Andrew Morton asked whether the allocation performed inside addtgt could use a more relaxed allocation like GFP_KERNEL, but addtgt is called when the aoedev lock has been locked with spin_lock_irqsave. It would be nice to allocate the memory under fewer restrictions, but targets are only added when the device is being discovered, and if the target can't be added right now, we can try again in a minute when then next AoE config query broadcast goes out. Andrew Morton pointed out that the "too many targets" message could be printed for failing GFP_ATOMIC allocations. The last patch in this series makes the messages more specific. Signed-off-by: Ed L. Cashin <ecashin@coraid.com> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 15:20:00 +03:00
aoecmd_cleanslate(d);
loop:
skb = aoecmd_ata_id(d);
spin_unlock_irqrestore(&d->lock, flags);
aoe: handle multiple network paths to AoE device A remote AoE device is something can process ATA commands and is identified by an AoE shelf number and an AoE slot number. Such a device might have more than one network interface, and it might be reachable by more than one local network interface. This patch tracks the available network paths available to each AoE device, allowing them to be used more efficiently. Andrew Morton asked about the call to msleep_interruptible in the revalidate function. Yes, if a signal is pending, then msleep_interruptible will not return 0. That means we will not loop but will call aoenet_xmit with a NULL skb, which is a noop. If the system is too low on memory or the aoe driver is too low on frames, then the user can hit control-C to interrupt the attempt to do a revalidate. I have added a comment to the code summarizing that. Andrew Morton asked whether the allocation performed inside addtgt could use a more relaxed allocation like GFP_KERNEL, but addtgt is called when the aoedev lock has been locked with spin_lock_irqsave. It would be nice to allocate the memory under fewer restrictions, but targets are only added when the device is being discovered, and if the target can't be added right now, we can try again in a minute when then next AoE config query broadcast goes out. Andrew Morton pointed out that the "too many targets" message could be printed for failing GFP_ATOMIC allocations. The last patch in this series makes the messages more specific. Signed-off-by: Ed L. Cashin <ecashin@coraid.com> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 15:20:00 +03:00
/* try again if we are able to sleep a bit,
* otherwise give up this revalidation
*/
if (!skb && !msleep_interruptible(200)) {
spin_lock_irqsave(&d->lock, flags);
goto loop;
}
if (skb) {
struct sk_buff_head queue;
__skb_queue_head_init(&queue);
__skb_queue_tail(&queue, skb);
aoenet_xmit(&queue);
}
aoecmd_cfg(major, minor);
return 0;
}
void
aoechr_error(char *msg)
{
struct ErrMsg *em;
char *mp;
ulong flags, n;
n = strlen(msg);
spin_lock_irqsave(&emsgs_lock, flags);
em = emsgs + emsgs_tail_idx;
if ((em->flags & EMFL_VALID)) {
bail: spin_unlock_irqrestore(&emsgs_lock, flags);
return;
}
mp = kmalloc(n, GFP_ATOMIC);
if (mp == NULL) {
printk(KERN_ERR "aoe: allocation failure, len=%ld\n", n);
goto bail;
}
memcpy(mp, msg, n);
em->msg = mp;
em->flags |= EMFL_VALID;
em->len = n;
emsgs_tail_idx++;
emsgs_tail_idx %= ARRAY_SIZE(emsgs);
spin_unlock_irqrestore(&emsgs_lock, flags);
if (nblocked_emsgs_readers)
complete(&emsgs_comp);
}
static ssize_t
aoechr_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offp)
{
int ret = -EINVAL;
switch ((unsigned long) filp->private_data) {
default:
printk(KERN_INFO "aoe: can't write to that file.\n");
break;
case MINOR_DISCOVER:
ret = discover();
break;
case MINOR_INTERFACES:
ret = interfaces(buf, cnt);
break;
case MINOR_REVALIDATE:
ret = revalidate(buf, cnt);
break;
case MINOR_FLUSH:
ret = aoedev_flush(buf, cnt);
}
if (ret == 0)
ret = cnt;
return ret;
}
static int
aoechr_open(struct inode *inode, struct file *filp)
{
int n, i;
mutex_lock(&aoechr_mutex);
n = iminor(inode);
filp->private_data = (void *) (unsigned long) n;
for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
if (chardevs[i].minor == n) {
mutex_unlock(&aoechr_mutex);
return 0;
}
mutex_unlock(&aoechr_mutex);
return -EINVAL;
}
static int
aoechr_rel(struct inode *inode, struct file *filp)
{
return 0;
}
static ssize_t
aoechr_read(struct file *filp, char __user *buf, size_t cnt, loff_t *off)
{
unsigned long n;
char *mp;
struct ErrMsg *em;
ssize_t len;
ulong flags;
n = (unsigned long) filp->private_data;
if (n != MINOR_ERR)
return -EFAULT;
spin_lock_irqsave(&emsgs_lock, flags);
for (;;) {
em = emsgs + emsgs_head_idx;
if ((em->flags & EMFL_VALID) != 0)
break;
if (filp->f_flags & O_NDELAY) {
spin_unlock_irqrestore(&emsgs_lock, flags);
return -EAGAIN;
}
nblocked_emsgs_readers++;
spin_unlock_irqrestore(&emsgs_lock, flags);
n = wait_for_completion_interruptible(&emsgs_comp);
spin_lock_irqsave(&emsgs_lock, flags);
nblocked_emsgs_readers--;
if (n) {
spin_unlock_irqrestore(&emsgs_lock, flags);
return -ERESTARTSYS;
}
}
if (em->len > cnt) {
spin_unlock_irqrestore(&emsgs_lock, flags);
return -EAGAIN;
}
mp = em->msg;
len = em->len;
em->msg = NULL;
em->flags &= ~EMFL_VALID;
emsgs_head_idx++;
emsgs_head_idx %= ARRAY_SIZE(emsgs);
spin_unlock_irqrestore(&emsgs_lock, flags);
n = copy_to_user(buf, mp, len);
kfree(mp);
return n == 0 ? len : -EFAULT;
}
static const struct file_operations aoe_fops = {
.write = aoechr_write,
.read = aoechr_read,
.open = aoechr_open,
.release = aoechr_rel,
.owner = THIS_MODULE,
llseek: automatically add .llseek fop All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Julia Lawall <julia@diku.dk> Cc: Christoph Hellwig <hch@infradead.org>
2010-08-15 20:52:59 +04:00
.llseek = noop_llseek,
};
static char *aoe_devnode(struct device *dev, mode_t *mode)
{
return kasprintf(GFP_KERNEL, "etherd/%s", dev_name(dev));
}
int __init
aoechr_init(void)
{
int n, i;
n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops);
if (n < 0) {
printk(KERN_ERR "aoe: can't register char device\n");
return n;
}
init_completion(&emsgs_comp);
spin_lock_init(&emsgs_lock);
aoe_class = class_create(THIS_MODULE, "aoe");
if (IS_ERR(aoe_class)) {
unregister_chrdev(AOE_MAJOR, "aoechr");
return PTR_ERR(aoe_class);
}
aoe_class->devnode = aoe_devnode;
for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
device_create(aoe_class, NULL,
MKDEV(AOE_MAJOR, chardevs[i].minor), NULL,
chardevs[i].name);
return 0;
}
void
aoechr_exit(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor));
class_destroy(aoe_class);
unregister_chrdev(AOE_MAJOR, "aoechr");
}