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Commit acd6d738 authored by Rob Evers's avatar Rob Evers Committed by Christoph Hellwig
Browse files

scsi: retry report-luns when reported LU count requres more memory 



Update scsi_report_lun_scan to initially always report up to 511 LUs,
as the previous default max_report_luns did.  Retry in a loop if not
enough memory is available for the number of LUs reported.  Parameter
max_report_luns is removed as it is no longer used.

Signed-off-by: default avatarRob Evers <revers@redhat.com>
Reviewed-by: default avatarEwan D. Milne <emilne@redhat.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 2a904e5d

drivers/scsi/scsi_scan.c

+11 −30
Original line number Diff line number Diff line
@@ -99,20 +99,6 @@ char scsi_scan_type[6] = SCSI_SCAN_TYPE_DEFAULT; 
module_param_string(scan, scsi_scan_type, sizeof(scsi_scan_type), S_IRUGO);

MODULE_PARM_DESC(scan, "sync, async or none");



/*

 * max_scsi_report_luns: the maximum number of LUNS that will be

 * returned from the REPORT LUNS command. 8 times this value must

 * be allocated. In theory this could be up to an 8 byte value, but

 * in practice, the maximum number of LUNs suppored by any device

 * is about 16k.

 */

static unsigned int max_scsi_report_luns = 511;



module_param_named(max_report_luns, max_scsi_report_luns, uint, S_IRUGO|S_IWUSR);

MODULE_PARM_DESC(max_report_luns,

		 "REPORT LUNS maximum number of LUNS received (should be"

		 " between 1 and 16384)");



static unsigned int scsi_inq_timeout = SCSI_TIMEOUT/HZ + 18;



module_param_named(inq_timeout, scsi_inq_timeout, uint, S_IRUGO|S_IWUSR);
@@ -1407,15 +1393,11 @@ static int scsi_report_lun_scan(struct scsi_target *starget, int bflags, 


	/*

	 * Allocate enough to hold the header (the same size as one scsi_lun)

	 * plus the max number of luns we are requesting.

	 *

	 * Reallocating and trying again (with the exact amount we need)

	 * would be nice, but then we need to somehow limit the size

	 * allocated based on the available memory and the limits of

	 * kmalloc - we don't want a kmalloc() failure of a huge value to

	 * prevent us from finding any LUNs on this target.

	 * plus the number of luns we are requesting.  511 was the default

	 * value of the now removed max_report_luns parameter.

	 */

	length = (max_scsi_report_luns + 1) * sizeof(struct scsi_lun);

	length = (511 + 1) * sizeof(struct scsi_lun);

retry:

	lun_data = kmalloc(length, GFP_KERNEL |

			   (sdev->host->unchecked_isa_dma ? __GFP_DMA : 0));

	if (!lun_data) {
@@ -1481,17 +1463,16 @@ static int scsi_report_lun_scan(struct scsi_target *starget, int bflags, 
	/*

	 * Get the length from the first four bytes of lun_data.

	 */

	if (get_unaligned_be32(lun_data->scsi_lun) +

	    sizeof(struct scsi_lun) > length) {

		length = get_unaligned_be32(lun_data->scsi_lun) +

			 sizeof(struct scsi_lun);

		kfree(lun_data);

		goto retry;

	}

	length = get_unaligned_be32(lun_data->scsi_lun);



	num_luns = (length / sizeof(struct scsi_lun));

	if (num_luns > max_scsi_report_luns) {

		sdev_printk(KERN_WARNING, sdev,

			    "Only %d (max_scsi_report_luns)"

			    " of %d luns reported, try increasing"

			    " max_scsi_report_luns.\n",

			    max_scsi_report_luns, num_luns);

		num_luns = max_scsi_report_luns;

	}



	SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,

		"scsi scan: REPORT LUN scan\n"));