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authorSebastian Siewior <bigeasy@linutronix.de>2008-07-04 09:59:56 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-04 10:40:08 -0700
commit4b1295b0df28cffd40e6c6d7c4b88dec7af1eb76 (patch)
treeea6414ba80a771c9ffdfd2c5e6c485c34ef671b4 /drivers/spi
parentbef67c5a7d3a9c45e091e36625c09c0c811e2672 (diff)
spi: fix the read path in spidev
This got broken by the recent "fix rmmod $spi_driver while spidev-user is active". I tested the rmmod & write path but didn't check the read path. I am sorry. The read logic changed and spidev_sync_read() + spidev_sync_write() do not return zero on success anymore but the number of bytes that has been transfered over the bus. This patch changes the logic and copy_to_user() gets called again. The write path returns the number of bytes which are written to the underlying device what may be less than the requested size. This patch makes the same change to the read path or else we request a read of 20 bytes, get 10, don't call copy to user and report to the user that we read 10 bytes. [akpm@linux-foundation.org: remove test of known-to-be-zero local] Signed-off-by: Sebastian Siewior <bigeasy@linutronix.de> Acked-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spidev.c10
1 files changed, 4 insertions, 6 deletions
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 799337f7fde..f5b60c70389 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -167,14 +167,14 @@ spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
mutex_lock(&spidev->buf_lock);
status = spidev_sync_read(spidev, count);
- if (status == 0) {
+ if (status > 0) {
unsigned long missing;
- missing = copy_to_user(buf, spidev->buffer, count);
- if (count && missing == count)
+ missing = copy_to_user(buf, spidev->buffer, status);
+ if (missing == status)
status = -EFAULT;
else
- status = count - missing;
+ status = status - missing;
}
mutex_unlock(&spidev->buf_lock);
@@ -200,8 +200,6 @@ spidev_write(struct file *filp, const char __user *buf,
missing = copy_from_user(spidev->buffer, buf, count);
if (missing == 0) {
status = spidev_sync_write(spidev, count);
- if (status == 0)
- status = count;
} else
status = -EFAULT;
mutex_unlock(&spidev->buf_lock);