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authorSebastian Siewior <bigeasy@linutronix.de>2008-07-04 12:59:56 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-04 13:40:08 -0400
commit4b1295b0df28cffd40e6c6d7c4b88dec7af1eb76 (patch)
treeea6414ba80a771c9ffdfd2c5e6c485c34ef671b4 /drivers
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')
-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 799337f7fde1..f5b60c70389b 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)
167 167
168 mutex_lock(&spidev->buf_lock); 168 mutex_lock(&spidev->buf_lock);
169 status = spidev_sync_read(spidev, count); 169 status = spidev_sync_read(spidev, count);
170 if (status == 0) { 170 if (status > 0) {
171 unsigned long missing; 171 unsigned long missing;
172 172
173 missing = copy_to_user(buf, spidev->buffer, count); 173 missing = copy_to_user(buf, spidev->buffer, status);
174 if (count && missing == count) 174 if (missing == status)
175 status = -EFAULT; 175 status = -EFAULT;
176 else 176 else
177 status = count - missing; 177 status = status - missing;
178 } 178 }
179 mutex_unlock(&spidev->buf_lock); 179 mutex_unlock(&spidev->buf_lock);
180 180
@@ -200,8 +200,6 @@ spidev_write(struct file *filp, const char __user *buf,
200 missing = copy_from_user(spidev->buffer, buf, count); 200 missing = copy_from_user(spidev->buffer, buf, count);
201 if (missing == 0) { 201 if (missing == 0) {
202 status = spidev_sync_write(spidev, count); 202 status = spidev_sync_write(spidev, count);
203 if (status == 0)
204 status = count;
205 } else 203 } else
206 status = -EFAULT; 204 status = -EFAULT;
207 mutex_unlock(&spidev->buf_lock); 205 mutex_unlock(&spidev->buf_lock);