This is a note to let you know that I've just added the patch titled
scsi: sd: Fix capacity calculation with 32-bit sector_t
to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
scsi-sd-fix-capacity-calculation-with-32-bit-sector_t.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7c856152cb92f8eee2df29ef325a1b1f43161aff Mon Sep 17 00:00:00 2001
From: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
Date: Tue, 4 Apr 2017 10:42:30 -0400
Subject: scsi: sd: Fix capacity calculation with 32-bit sector_t
From: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
commit 7c856152cb92f8eee2df29ef325a1b1f43161aff upstream.
We previously made sure that the reported disk capacity was less than
0xffffffff blocks when the kernel was not compiled with large sector_t
support (CONFIG_LBDAF). However, this check assumed that the capacity
was reported in units of 512 bytes.
Add a sanity check function to ensure that we only enable disks if the
entire reported capacity can be expressed in terms of sector_t.
Reported-by: Steve Magnani <steve.magnani@xxxxxxxxxxxxxxx>
Cc: Bart Van Assche <Bart.VanAssche@xxxxxxxxxxx>
Reviewed-by: Bart Van Assche <Bart.VanAssche@xxxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/scsi/sd.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1979,6 +1979,22 @@ static void read_capacity_error(struct s
#define READ_CAPACITY_RETRIES_ON_RESET 10
+/*
+ * Ensure that we don't overflow sector_t when CONFIG_LBDAF is not set
+ * and the reported logical block size is bigger than 512 bytes. Note
+ * that last_sector is a u64 and therefore logical_to_sectors() is not
+ * applicable.
+ */
+static bool sd_addressable_capacity(u64 lba, unsigned int sector_size)
+{
+ u64 last_sector = (lba + 1ULL) << (ilog2(sector_size) - 9);
+
+ if (sizeof(sector_t) == 4 && last_sector > U32_MAX)
+ return false;
+
+ return true;
+}
+
static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
unsigned char *buffer)
{
@@ -2044,7 +2060,7 @@ static int read_capacity_16(struct scsi_
return -ENODEV;
}
- if ((sizeof(sdkp->capacity) == 4) && (lba >= 0xffffffffULL)) {
+ if (!sd_addressable_capacity(lba, sector_size)) {
sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use a "
"kernel compiled with support for large block "
"devices.\n");
@@ -2130,7 +2146,7 @@ static int read_capacity_10(struct scsi_
return sector_size;
}
- if ((sizeof(sdkp->capacity) == 4) && (lba == 0xffffffff)) {
+ if (!sd_addressable_capacity(lba, sector_size)) {
sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use a "
"kernel compiled with support for large block "
"devices.\n");
Patches currently in stable-queue which might be from martin.petersen@xxxxxxxxxx are
queue-3.18/scsi-sr-sanity-check-returned-mode-data.patch
queue-3.18/scsi-sd-fix-capacity-calculation-with-32-bit-sector_t.patch