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Commit c25d75a2 authored by Nitin Gupta's avatar Nitin Gupta Committed by Greg Kroah-Hartman
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Staging: ramzswap: Handle case for invalid backing swap 



Currently, we crash (issue BUG_ON) if backing swap
disk size is zero. This can happen is user specified
an extended partition or simply a bad disk as backing
swap. A crash is really an unpleasant surprise to user
for such trivial problems.

Now, we check for this condition and simply fail device
initialization if this is the case.

Additional cleanups:
 * use static for all functions
 * remove extra newline between functions
 * memset backing_swap_name to NULL on device reset

Signed-off-by: default avatarNitin Gupta <ngupta@vflare.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 2e882281

drivers/staging/ramzswap/ramzswap_drv.c

+11 −5
Original line number Diff line number Diff line
@@ -220,7 +220,7 @@ static int setup_swap_header(struct ramzswap *rzs, union swap_header *s) 
	return ret;

}



void ramzswap_ioctl_get_stats(struct ramzswap *rzs,

static void ramzswap_ioctl_get_stats(struct ramzswap *rzs,

			struct ramzswap_ioctl_stats *s)

{

	strncpy(s->backing_swap_name, rzs->backing_swap_name,
@@ -502,6 +502,14 @@ static int setup_backing_swap(struct ramzswap *rzs) 
			goto bad_param;

		}

		disksize = i_size_read(inode);

		/*

		 * Can happen if user gives an extended partition as

		 * backing swap or simply a bad disk.

		 */

		if (!disksize) {

			pr_err("Error reading backing swap size.\n");

			goto bad_param;

		}

	} else if (S_ISREG(inode->i_mode)) {

		bdev = inode->i_sb->s_bdev;

		if (IS_SWAPFILE(inode)) {
@@ -519,7 +527,6 @@ static int setup_backing_swap(struct ramzswap *rzs) 
	rzs->swap_file = swap_file;

	rzs->backing_swap = bdev;

	rzs->disksize = disksize;

	BUG_ON(!rzs->disksize);



	return 0;
@@ -537,7 +544,7 @@ static int setup_backing_swap(struct ramzswap *rzs) 
 * Map logical page number 'pagenum' to physical page number

 * on backing swap device. For block device, this is a nop.

 */

u32 map_backing_swap_page(struct ramzswap *rzs, u32 pagenum)

static u32 map_backing_swap_page(struct ramzswap *rzs, u32 pagenum)

{

	u32 skip_pages, entries_per_page;

	size_t delta, se_offset, skipped;
@@ -668,7 +675,6 @@ static int handle_uncompressed_page(struct ramzswap *rzs, struct bio *bio) 
	return 0;

}





/*

 * Called when request page is not present in ramzswap.

 * Its either in backing swap device (if present) or
@@ -936,7 +942,6 @@ static int ramzswap_write(struct ramzswap *rzs, struct bio *bio) 
	return 0;

}





/*

 * Check if request is within bounds and page aligned.

 */
@@ -1064,6 +1069,7 @@ static void reset_device(struct ramzswap *rzs) 
			bd_release(rzs->backing_swap);

		filp_close(rzs->swap_file, NULL);

		rzs->backing_swap = NULL;

		memset(rzs->backing_swap_name, 0, MAX_SWAP_NAME_LEN);

	}



	/* Reset stats */