From: Sebastian Siewior Date: Fri, 4 Jul 2008 16:59:56 +0000 (-0700) Subject: spi: fix the read path in spidev X-Git-Tag: v2.6.26-rc9~25 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4b1295b0df28cffd40e6c6d7c4b88dec7af1eb76;p=linux-2.6 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 Acked-by: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c index 799337f7fd..f5b60c7038 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);