On 3/6/23 19:01, Keith Busch wrote:
On Mon, Mar 06, 2023 at 01:01:26PM +0100, Hannes Reinecke wrote:
Use an arbitrary limit of 32M for the maximal blocksize so as not
to overflow the page cache.
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
drivers/block/brd.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 11bac3c3f1b6..1ed114cd5cb0 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -348,6 +348,7 @@ static int max_part = 1;
module_param(max_part, int, 0444);
MODULE_PARM_DESC(max_part, "Num Minors to reserve between devices");
+#define RD_MAX_SECTOR_SIZE 65536
static unsigned int rd_blksize = PAGE_SIZE;
module_param(rd_blksize, uint, 0444);
MODULE_PARM_DESC(rd_blksize, "Blocksize of each RAM disk in bytes.");
@@ -410,15 +411,14 @@ static int brd_alloc(int i)
disk->private_data = brd;
strscpy(disk->disk_name, buf, DISK_NAME_LEN);
set_capacity(disk, rd_size * 2);
-
- /*
- * This is so fdisk will align partitions on 4k, because of
- * direct_access API needing 4k alignment, returning a PFN
- * (This is only a problem on very small devices <= 4M,
- * otherwise fdisk will align on 1M. Regardless this call
- * is harmless)
- */
+
+ if (rd_blksize > RD_MAX_SECTOR_SIZE) {
rd_blkside is in bytes, but the above is ccomapring it to something in units of
SECTOR_SIZE.
Ok.
+ /* Arbitrary limit maximum block size to 32M */
+ err = -EINVAL;
+ goto out_cleanup_disk;
+ }
rd_blksize also needs to be >= 512, and a power of 2.
Yes; I'll be adding the checks accordingly.
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
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