scsi: sd_zbc: Cleanup sd_zbc_alloc_report_buffer() (23a50861) · Commits · 戴 / test

There is no need to arbitrarily limit the size of a report zone to the number of zones defined by SD_ZBC_REPORT_MAX_ZONES. Rather, simply calculate the report buffer size needed for the requested number of zones without exceeding the device total number of zones. This buffer size limitation to the hardware maximum transfer size and page mapping capabilities is kept unchanged. Starting with this initial buffer size, the allocation is optimized by iterating over decreasing buffer size until the allocation succeeds (each iteration is allowed to fail fast using the __GFP_NORETRY flag). This ensures forward progress for zone reports and avoids failures of zones revalidation under memory pressure. While at it, also replace the hard coded 512 B sector size with the SECTOR_SIZE macro. Reviewed-by:

Hannes Reinecke <hare@suse.de> Reviewed-by:

Christoph Hellwig <hch@lst.de> Acked-by:

Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by:

Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by:

Jens Axboe <axboe@kernel.dk>

drivers/scsi/sd_zbc.c

+13 −11

Original line number	Diff line number	Diff line
		@@ -104,11 +104,6 @@ static int sd_zbc_do_report_zones(struct scsi_disk sdkp, unsigned char buf,
		return 0;
		}

		/*
		* Maximum number of zones to get with one report zones command.
		*/
		#define SD_ZBC_REPORT_MAX_ZONES 8192U

		/**
		* Allocate a buffer for report zones reply.
		* @sdkp: The target disk
		@@ -138,18 +133,25 @@ static void sd_zbc_alloc_report_buffer(struct scsi_disk sdkp,
		* sure that the allocated buffer can always be mapped by limiting the
		* number of pages allocated to the HBA max segments limit.
		*/
		nr_zones = min(nr_zones, SD_ZBC_REPORT_MAX_ZONES);
		bufsize = roundup((nr_zones + 1) * 64, 512);
		nr_zones = min(nr_zones, sdkp->nr_zones);
		bufsize = roundup((nr_zones + 1) * 64, SECTOR_SIZE);
		bufsize = min_t(size_t, bufsize,
		queue_max_hw_sectors(q) << SECTOR_SHIFT);
		bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);

		buf = vzalloc(bufsize);
		if (buf)
		while (bufsize >= SECTOR_SIZE) {
		buf = __vmalloc(bufsize,
		GFP_KERNEL \| __GFP_ZERO \| __GFP_NORETRY,
		PAGE_KERNEL);
		if (buf) {
		*buflen = bufsize;

		return buf;
		}
		bufsize >>= 1;
		}

		return NULL;
		}

		/**
		* sd_zbc_report_zones - Disk report zones operation.

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