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mei: always copy the read buffer if data is ready 

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>
hifive-unleashed-5.1
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
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@ -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);