Commit 7c856152 authored by Martin K. Petersen's avatar Martin K. Petersen
Browse files

scsi: sd: Fix capacity calculation with 32-bit sector_t 



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.

Cc: <stable@vger.kernel.org>
Reported-by: default avatarSteve Magnani <steve.magnani@digidescorp.com>
Cc: Bart Van Assche <Bart.VanAssche@sandisk.com>
Reviewed-by: default avatarBart Van Assche <Bart.VanAssche@sandisk.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent bf6061b1

drivers/scsi/sd.c

+18 −2
Original line number Diff line number Diff line
@@ -2102,6 +2102,22 @@ static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp, 


#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)

{
@@ -2167,7 +2183,7 @@ static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp, 
		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");
@@ -2256,7 +2272,7 @@ static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp, 
		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");

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