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mei: always copy the read buffer if data is ready

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Copy completed callback content to the user space
if we have such callback ready in the beginning of the read.
Simplify offset processing logic as byproduct.

This is a refinement for:
commit 139aacf757 ("mei: fix read after read scenario")

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alexander Usyskin 2016-01-07 14:46:37 +02:00 committed by Greg Kroah-Hartman
parent 13cf988562
commit 8b2458f413
1 changed files with 14 additions and 18 deletions
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32
drivers/misc/mei/main.c
View File

@ -159,27 +159,22 @@ static ssize_t mei_read(struct file *file, char __user *ubuf,
goto out;
}
if (ubuf == NULL) {
rets = -EMSGSIZE;
goto out;
}
if (cl == &dev->iamthif_cl) {
rets = mei_amthif_read(dev, file, ubuf, length, offset);
goto out;
}
cb = mei_cl_read_cb(cl, file);
if (cb) {
/* read what left */
if (cb->buf_idx > *offset)
goto copy_buffer;
/* offset is beyond buf_idx we have no more data return 0 */
if (cb->buf_idx > 0 && cb->buf_idx <= *offset) {
rets = 0;
goto free;
}
/* Offset needs to be cleaned for contiguous reads*/
if (cb->buf_idx == 0 && *offset > 0)
*offset = 0;
} else if (*offset > 0) {
if (cb)
goto copy_buffer;
if (*offset > 0)
*offset = 0;
}
err = mei_cl_read_start(cl, length, file);
if (err && err != -EBUSY) {
@ -231,10 +226,10 @@ copy_buffer:
goto free;
}
cl_dbg(dev, cl, "buf.size = %d buf.idx = %ld\n",
cb->buf.size, cb->buf_idx);
if (length == 0 || ubuf == NULL || *offset > cb->buf_idx) {
rets = -EMSGSIZE;
cl_dbg(dev, cl, "buf.size = %d buf.idx = %ld offset = %lld\n",
cb->buf.size, cb->buf_idx, *offset);
if (*offset >= cb->buf_idx) {
rets = 0;
goto free;
}
@ -255,6 +250,7 @@ copy_buffer:
free:
mei_io_cb_free(cb);
*offset = 0;
out:
cl_dbg(dev, cl, "end mei read rets = %d\n", rets);