diff options
Diffstat (limited to 'drivers/scsi/sg.c')
| -rw-r--r-- | drivers/scsi/sg.c | 53 |
1 files changed, 40 insertions, 13 deletions
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 34f9343ed0a..3f8b9318856 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -60,7 +60,7 @@ static int sg_version_num = 30534; /* 2 digits for each component */ #ifdef CONFIG_SCSI_PROC_FS #include <linux/proc_fs.h> -static char *sg_version_date = "20060818"; +static char *sg_version_date = "20060920"; static int sg_proc_init(void); static void sg_proc_cleanup(void); @@ -94,6 +94,9 @@ int sg_big_buff = SG_DEF_RESERVED_SIZE; static int def_reserved_size = -1; /* picks up init parameter */ static int sg_allow_dio = SG_ALLOW_DIO_DEF; +static int scatter_elem_sz = SG_SCATTER_SZ; +static int scatter_elem_sz_prev = SG_SCATTER_SZ; + #define SG_SECTOR_SZ 512 #define SG_SECTOR_MSK (SG_SECTOR_SZ - 1) @@ -1537,11 +1540,9 @@ sg_remove(struct class_device *cl_dev, struct class_interface *cl_intf) msleep(10); /* dirty detach so delay device destruction */ } -/* Set 'perm' (4th argument) to 0 to disable module_param's definition - * of sysfs parameters (which module_param doesn't yet support). - * Sysfs parameters defined explicitly below. - */ -module_param_named(def_reserved_size, def_reserved_size, int, S_IRUGO); +module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR); +module_param_named(def_reserved_size, def_reserved_size, int, + S_IRUGO | S_IWUSR); module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR); MODULE_AUTHOR("Douglas Gilbert"); @@ -1550,6 +1551,8 @@ MODULE_LICENSE("GPL"); MODULE_VERSION(SG_VERSION_STR); MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR); +MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element " + "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))"); MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd"); MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))"); @@ -1558,8 +1561,14 @@ init_sg(void) { int rc; + if (scatter_elem_sz < PAGE_SIZE) { + scatter_elem_sz = PAGE_SIZE; + scatter_elem_sz_prev = scatter_elem_sz; + } if (def_reserved_size >= 0) sg_big_buff = def_reserved_size; + else + def_reserved_size = sg_big_buff; rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS, "sg"); @@ -1842,15 +1851,30 @@ sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size) if (mx_sc_elems < 0) return mx_sc_elems; /* most likely -ENOMEM */ + num = scatter_elem_sz; + if (unlikely(num != scatter_elem_sz_prev)) { + if (num < PAGE_SIZE) { + scatter_elem_sz = PAGE_SIZE; + scatter_elem_sz_prev = PAGE_SIZE; + } else + scatter_elem_sz_prev = num; + } for (k = 0, sg = schp->buffer, rem_sz = blk_size; (rem_sz > 0) && (k < mx_sc_elems); ++k, rem_sz -= ret_sz, ++sg) { - num = (rem_sz > SG_SCATTER_SZ) ? SG_SCATTER_SZ : rem_sz; + num = (rem_sz > scatter_elem_sz_prev) ? + scatter_elem_sz_prev : rem_sz; p = sg_page_malloc(num, sfp->low_dma, &ret_sz); if (!p) return -ENOMEM; + if (num == scatter_elem_sz_prev) { + if (unlikely(ret_sz > scatter_elem_sz_prev)) { + scatter_elem_sz = ret_sz; + scatter_elem_sz_prev = ret_sz; + } + } sg->page = p; sg->length = ret_sz; @@ -2341,6 +2365,9 @@ sg_add_sfp(Sg_device * sdp, int dev) } write_unlock_irqrestore(&sg_dev_arr_lock, iflags); SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp)); + if (unlikely(sg_big_buff != def_reserved_size)) + sg_big_buff = def_reserved_size; + sg_build_reserve(sfp, sg_big_buff); SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: bufflen=%d, k_use_sg=%d\n", sfp->reserve.bufflen, sfp->reserve.k_use_sg)); @@ -2437,16 +2464,16 @@ sg_res_in_use(Sg_fd * sfp) return srp ? 1 : 0; } -/* If retSzp==NULL want exact size or fail */ +/* The size fetched (value output via retSzp) set when non-NULL return */ static struct page * sg_page_malloc(int rqSz, int lowDma, int *retSzp) { struct page *resp = NULL; gfp_t page_mask; int order, a_size; - int resSz = rqSz; + int resSz; - if (rqSz <= 0) + if ((rqSz <= 0) || (NULL == retSzp)) return resp; if (lowDma) @@ -2456,8 +2483,9 @@ sg_page_malloc(int rqSz, int lowDma, int *retSzp) for (order = 0, a_size = PAGE_SIZE; a_size < rqSz; order++, a_size <<= 1) ; + resSz = a_size; /* rounded up if necessary */ resp = alloc_pages(page_mask, order); - while ((!resp) && order && retSzp) { + while ((!resp) && order) { --order; a_size >>= 1; /* divide by 2, until PAGE_SIZE */ resp = alloc_pages(page_mask, order); /* try half */ @@ -2466,8 +2494,7 @@ sg_page_malloc(int rqSz, int lowDma, int *retSzp) if (resp) { if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO)) memset(page_address(resp), 0, resSz); - if (retSzp) - *retSzp = resSz; + *retSzp = resSz; } return resp; } |