c8070b7875
Make pin_user_pages*() leave a ZERO_PAGE unpinned if it extracts a pointer to it from the page tables and make unpin_user_page*() correspondingly ignore a ZERO_PAGE when unpinning. We don't want to risk overrunning a zero page's refcount as we're only allowed ~2 million pins on it - something that userspace can conceivably trigger. Add a pair of functions to test whether a page or a folio is a ZERO_PAGE. Signed-off-by: David Howells <dhowells@redhat.com> cc: Christoph Hellwig <hch@infradead.org> cc: David Hildenbrand <david@redhat.com> cc: Lorenzo Stoakes <lstoakes@gmail.com> cc: Andrew Morton <akpm@linux-foundation.org> cc: Jens Axboe <axboe@kernel.dk> cc: Al Viro <viro@zeniv.linux.org.uk> cc: Matthew Wilcox <willy@infradead.org> cc: Jan Kara <jack@suse.cz> cc: Jeff Layton <jlayton@kernel.org> cc: Jason Gunthorpe <jgg@nvidia.com> cc: Logan Gunthorpe <logang@deltatee.com> cc: Hillf Danton <hdanton@sina.com> cc: Christian Brauner <brauner@kernel.org> cc: Linus Torvalds <torvalds@linux-foundation.org> cc: linux-fsdevel@vger.kernel.org cc: linux-block@vger.kernel.org cc: linux-kernel@vger.kernel.org cc: linux-mm@kvack.org Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20230526214142.958751-2-dhowells@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk> |
||
---|---|---|
.. | ||
ABI | ||
accel | ||
accounting | ||
admin-guide | ||
arch | ||
arm | ||
arm64 | ||
block | ||
bpf | ||
cdrom | ||
core-api | ||
cpu-freq | ||
crypto | ||
dev-tools | ||
devicetree | ||
doc-guide | ||
driver-api | ||
fault-injection | ||
fb | ||
features | ||
filesystems | ||
firmware_class | ||
firmware-guide | ||
fpga | ||
gpu | ||
hid | ||
hwmon | ||
i2c | ||
iio | ||
images | ||
infiniband | ||
input | ||
isdn | ||
kbuild | ||
kernel-hacking | ||
leds | ||
litmus-tests | ||
livepatch | ||
locking | ||
loongarch | ||
maintainer | ||
mhi | ||
mips | ||
misc-devices | ||
mm | ||
netlabel | ||
netlink | ||
networking | ||
nvdimm | ||
nvme | ||
PCI | ||
pcmcia | ||
peci | ||
power | ||
powerpc | ||
process | ||
RCU | ||
riscv | ||
rust | ||
s390 | ||
scheduler | ||
scsi | ||
security | ||
sound | ||
sphinx | ||
sphinx-static | ||
spi | ||
staging | ||
target | ||
timers | ||
tools | ||
trace | ||
translations | ||
usb | ||
userspace-api | ||
virt | ||
w1 | ||
watchdog | ||
.gitignore | ||
atomic_bitops.txt | ||
atomic_t.txt | ||
Changes | ||
CodingStyle | ||
conf.py | ||
docutils.conf | ||
dontdiff | ||
index.rst | ||
Kconfig | ||
Makefile | ||
memory-barriers.txt | ||
SubmittingPatches | ||
subsystem-apis.rst |