From acd6d73826224c20c44f505f56b0503f022d695c Mon Sep 17 00:00:00 2001 From: Rob Evers Date: Tue, 16 Dec 2014 11:01:20 -0500 Subject: [PATCH] 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: Rob Evers Reviewed-by: Ewan D. Milne Signed-off-by: Christoph Hellwig --- drivers/scsi/scsi_scan.c | 41 +++++++++++----------------------------- 1 file changed, 11 insertions(+), 30 deletions(-) diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index b7948d20c23b..0deb385ad4d6 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -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")); -- 2.20.1