From: Akinobu Mita Date: Mon, 8 Jul 2013 23:01:57 +0000 (-0700) Subject: scsi_debug: fix do_device_access() with wrap around range X-Git-Tag: Ubuntu-5.2.0-15.16~15328^2~1 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=a451751172b39702e94c683882ab01d816b673c7;p=mirror_ubuntu-eoan-kernel.git scsi_debug: fix do_device_access() with wrap around range do_device_access() is a function that abstracts copying SG list from/to ramdisk storage (fake_storep). It must deal with the ranges exceeding actual fake_storep size, because such ranges are valid if virtual_gb is set greater than zero, and they should be treated as fake_storep is repeatedly mirrored up to virtual size. Unfortunately, it can't deal with the range which wraps around the end of fake_storep. A wrap around range is copied by two sg_copy_{from,to}_buffer() calls, but sg_copy_{from,to}_buffer() can't copy from/to in the middle of SG list, therefore the second call can't copy correctly. This fixes it by using sg_pcopy_{from,to}_buffer() that can copy from/to the middle of SG list. This also simplifies the assignment of sdb->resid in fill_from_dev_buffer(). Because fill_from_dev_buffer() is now only called once per command execution cycle. So it is not necessary to take care to decrease sdb->resid if fill_from_dev_buffer() is called more than once. Signed-off-by: Akinobu Mita Cc: "David S. Miller" Cc: "James E.J. Bottomley" Cc: Douglas Gilbert Cc: Herbert Xu Cc: Horia Geanta Cc: Imre Deak Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c index 0a537a0515ca..d055450c2a4a 100644 --- a/drivers/scsi/scsi_debug.c +++ b/drivers/scsi/scsi_debug.c @@ -439,10 +439,7 @@ static int fill_from_dev_buffer(struct scsi_cmnd *scp, unsigned char *arr, act_len = sg_copy_from_buffer(sdb->table.sgl, sdb->table.nents, arr, arr_len); - if (sdb->resid) - sdb->resid -= act_len; - else - sdb->resid = scsi_bufflen(scp) - act_len; + sdb->resid = scsi_bufflen(scp) - act_len; return 0; } @@ -1693,24 +1690,48 @@ static int check_device_access_params(struct sdebug_dev_info *devi, return 0; } +/* Returns number of bytes copied or -1 if error. */ static int do_device_access(struct scsi_cmnd *scmd, struct sdebug_dev_info *devi, unsigned long long lba, unsigned int num, int write) { int ret; unsigned long long block, rest = 0; - int (*func)(struct scsi_cmnd *, unsigned char *, int); + struct scsi_data_buffer *sdb; + enum dma_data_direction dir; + size_t (*func)(struct scatterlist *, unsigned int, void *, size_t, + off_t); + + if (write) { + sdb = scsi_out(scmd); + dir = DMA_TO_DEVICE; + func = sg_pcopy_to_buffer; + } else { + sdb = scsi_in(scmd); + dir = DMA_FROM_DEVICE; + func = sg_pcopy_from_buffer; + } - func = write ? fetch_to_dev_buffer : fill_from_dev_buffer; + if (!sdb->length) + return 0; + if (!(scsi_bidi_cmnd(scmd) || scmd->sc_data_direction == dir)) + return -1; block = do_div(lba, sdebug_store_sectors); if (block + num > sdebug_store_sectors) rest = block + num - sdebug_store_sectors; - ret = func(scmd, fake_storep + (block * scsi_debug_sector_size), - (num - rest) * scsi_debug_sector_size); - if (!ret && rest) - ret = func(scmd, fake_storep, rest * scsi_debug_sector_size); + ret = func(sdb->table.sgl, sdb->table.nents, + fake_storep + (block * scsi_debug_sector_size), + (num - rest) * scsi_debug_sector_size, 0); + if (ret != (num - rest) * scsi_debug_sector_size) + return ret; + + if (rest) { + ret += func(sdb->table.sgl, sdb->table.nents, + fake_storep, rest * scsi_debug_sector_size, + (num - rest) * scsi_debug_sector_size); + } return ret; } @@ -1849,7 +1870,12 @@ static int resp_read(struct scsi_cmnd *SCpnt, unsigned long long lba, read_lock_irqsave(&atomic_rw, iflags); ret = do_device_access(SCpnt, devip, lba, num, 0); read_unlock_irqrestore(&atomic_rw, iflags); - return ret; + if (ret == -1) + return DID_ERROR << 16; + + scsi_in(SCpnt)->resid = scsi_bufflen(SCpnt) - ret; + + return 0; } void dump_sector(unsigned char *buf, int len)