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Subject[PATCH -mm] updated idetape gcc 4.1 warning fix
Another idetape fixup attempt.

In both the read and write cases it will return an error if copy_{from/to}_user
faults. However, I let the driver try to read/write as much as it can just
as it normally would , then finally it returns an error if there was one.
This was the most straight forward way to handle the error , since there
isn't a clear way to clean up the buffers on error .

I moved retval in idetape_chrdev_write() down into the actual code blocks
since it's really once used there, and it conflicted with my ret variable.

Fixes the following warning,

drivers/ide/ide-tape.c: In function ‘idetape_copy_stage_from_user’:
drivers/ide/ide-tape.c:2662: warning: ignoring return value of ‘copy_from_user’, declared with attribute warn_unused_result
drivers/ide/ide-tape.c: In function ‘idetape_copy_stage_to_user’:
drivers/ide/ide-tape.c:2689: warning: ignoring return value of ‘copy_to_user’, declared with attribute warn_unused_result

Signed-Off-By: Daniel Walker <dwalker@mvista.com>

Index: linux-2.6.16/drivers/ide/ide-tape.c
===================================================================
--- linux-2.6.16.orig/drivers/ide/ide-tape.c
+++ linux-2.6.16/drivers/ide/ide-tape.c
@@ -2646,21 +2646,23 @@ static idetape_stage_t *idetape_kmalloc_
return __idetape_kmalloc_stage(tape, 0, 0);
}

-static void idetape_copy_stage_from_user (idetape_tape_t *tape, idetape_stage_t *stage, const char __user *buf, int n)
+static int idetape_copy_stage_from_user (idetape_tape_t *tape, idetape_stage_t *stage, const char __user *buf, int n)
{
struct idetape_bh *bh = tape->bh;
int count;
+ int ret = 0;

while (n) {
#if IDETAPE_DEBUG_BUGS
if (bh == NULL) {
printk(KERN_ERR "ide-tape: bh == NULL in "
"idetape_copy_stage_from_user\n");
- return;
+ return 1;
}
#endif /* IDETAPE_DEBUG_BUGS */
count = min((unsigned int)(bh->b_size - atomic_read(&bh->b_count)), (unsigned int)n);
- copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf, count);
+ if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf, count))
+ ret = 1;
n -= count;
atomic_add(count, &bh->b_count);
buf += count;
@@ -2671,23 +2673,26 @@ static void idetape_copy_stage_from_user
}
}
tape->bh = bh;
+ return ret;
}

-static void idetape_copy_stage_to_user (idetape_tape_t *tape, char __user *buf, idetape_stage_t *stage, int n)
+static int idetape_copy_stage_to_user (idetape_tape_t *tape, char __user *buf, idetape_stage_t *stage, int n)
{
struct idetape_bh *bh = tape->bh;
int count;
+ int ret = 0;

while (n) {
#if IDETAPE_DEBUG_BUGS
if (bh == NULL) {
printk(KERN_ERR "ide-tape: bh == NULL in "
"idetape_copy_stage_to_user\n");
- return;
+ return 1;
}
#endif /* IDETAPE_DEBUG_BUGS */
count = min(tape->b_count, n);
- copy_to_user(buf, tape->b_data, count);
+ if (copy_to_user(buf, tape->b_data, count))
+ ret = 1;
n -= count;
tape->b_data += count;
tape->b_count -= count;
@@ -2700,6 +2705,7 @@ static void idetape_copy_stage_to_user (
}
}
}
+ return ret;
}

static void idetape_init_merge_stage (idetape_tape_t *tape)
@@ -3719,6 +3725,7 @@ static ssize_t idetape_chrdev_read (stru
struct ide_tape_obj *tape = ide_tape_f(file);
ide_drive_t *drive = tape->drive;
ssize_t bytes_read,temp, actually_read = 0, rc;
+ ssize_t ret = 0;

#if IDETAPE_DEBUG_LOG
if (tape->debug_level >= 3)
@@ -3737,7 +3744,8 @@ static ssize_t idetape_chrdev_read (stru
return (0);
if (tape->merge_stage_size) {
actually_read = min((unsigned int)(tape->merge_stage_size), (unsigned int)count);
- idetape_copy_stage_to_user(tape, buf, tape->merge_stage, actually_read);
+ if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage, actually_read))
+ ret = -EFAULT;
buf += actually_read;
tape->merge_stage_size -= actually_read;
count -= actually_read;
@@ -3746,7 +3754,8 @@ static ssize_t idetape_chrdev_read (stru
bytes_read = idetape_add_chrdev_read_request(drive, tape->capabilities.ctl);
if (bytes_read <= 0)
goto finish;
- idetape_copy_stage_to_user(tape, buf, tape->merge_stage, bytes_read);
+ if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage, bytes_read))
+ ret = -EFAULT;
buf += bytes_read;
count -= bytes_read;
actually_read += bytes_read;
@@ -3756,7 +3765,8 @@ static ssize_t idetape_chrdev_read (stru
if (bytes_read <= 0)
goto finish;
temp = min((unsigned long)count, (unsigned long)bytes_read);
- idetape_copy_stage_to_user(tape, buf, tape->merge_stage, temp);
+ if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage, temp))
+ ret = -EFAULT;
actually_read += temp;
tape->merge_stage_size = bytes_read-temp;
}
@@ -3769,7 +3779,8 @@ finish:
idetape_space_over_filemarks(drive, MTFSF, 1);
return 0;
}
- return actually_read;
+
+ return (ret) ? ret : actually_read;
}

static ssize_t idetape_chrdev_write (struct file *file, const char __user *buf,
@@ -3777,7 +3788,8 @@ static ssize_t idetape_chrdev_write (str
{
struct ide_tape_obj *tape = ide_tape_f(file);
ide_drive_t *drive = tape->drive;
- ssize_t retval, actually_written = 0;
+ ssize_t actually_written = 0;
+ ssize_t ret = 0;

/* The drive is write protected. */
if (tape->write_prot)
@@ -3813,7 +3825,7 @@ static ssize_t idetape_chrdev_write (str
* some drives (Seagate STT3401A) will return an error.
*/
if (drive->dsc_overlap) {
- retval = idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 0, tape->merge_stage->bh);
+ ssize_t retval = idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 0, tape->merge_stage->bh);
if (retval < 0) {
__idetape_kfree_stage(tape->merge_stage);
tape->merge_stage = NULL;
@@ -3834,12 +3846,14 @@ static ssize_t idetape_chrdev_write (str
}
#endif /* IDETAPE_DEBUG_BUGS */
actually_written = min((unsigned int)(tape->stage_size - tape->merge_stage_size), (unsigned int)count);
- idetape_copy_stage_from_user(tape, tape->merge_stage, buf, actually_written);
+ if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf, actually_written))
+ ret = -EFAULT;
buf += actually_written;
tape->merge_stage_size += actually_written;
count -= actually_written;

if (tape->merge_stage_size == tape->stage_size) {
+ ssize_t retval;
tape->merge_stage_size = 0;
retval = idetape_add_chrdev_write_request(drive, tape->capabilities.ctl);
if (retval <= 0)
@@ -3847,7 +3861,9 @@ static ssize_t idetape_chrdev_write (str
}
}
while (count >= tape->stage_size) {
- idetape_copy_stage_from_user(tape, tape->merge_stage, buf, tape->stage_size);
+ ssize_t retval;
+ if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf, tape->stage_size))
+ ret = -EFAULT;
buf += tape->stage_size;
count -= tape->stage_size;
retval = idetape_add_chrdev_write_request(drive, tape->capabilities.ctl);
@@ -3857,10 +3873,11 @@ static ssize_t idetape_chrdev_write (str
}
if (count) {
actually_written += count;
- idetape_copy_stage_from_user(tape, tape->merge_stage, buf, count);
+ if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf, count))
+ ret = -EFAULT;
tape->merge_stage_size += count;
}
- return (actually_written);
+ return (ret) ? ret : actually_written;
}

static int idetape_write_filemark (ide_drive_t *drive)
-
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