From 10db10d144c0248f285242f79daf6b9de6b00a62 Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Fri, 29 Aug 2008 12:32:18 +0200 Subject: [PATCH] sg: convert the indirect IO path to use the block layer This patch converts the indirect IO path (including mmap IO and old struct sg_header) to use the block layer functions (blk_get_request, blk_execute_rq_nowait, blk_rq_map_user, etc) instead of scsi_execute_async(). [Jens: fixed compile error with SCSI logging enabled] Signed-off-by: FUJITA Tomonori Signed-off-by: Douglas Gilbert Cc: Mike Christie Cc: James Bottomley Signed-off-by: Jens Axboe --- drivers/scsi/sg.c | 397 ++++++++++++---------------------------------- 1 file changed, 105 insertions(+), 292 deletions(-) diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index cb6de0752ee1..d6391666502c 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -47,7 +47,6 @@ static int sg_version_num = 30534; /* 2 digits for each component */ #include #include #include -#include #include #include @@ -119,7 +118,8 @@ typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info */ unsigned sglist_len; /* size of malloc'd scatter-gather list ++ */ unsigned bufflen; /* Size of (aggregate) data buffer */ unsigned b_malloc_len; /* actual len malloc'ed in buffer */ - struct scatterlist *buffer;/* scatter list */ + struct page **pages; + int page_order; char dio_in_use; /* 0->indirect IO (or mmap), 1->dio */ unsigned char cmd_opcode; /* first byte of command */ } Sg_scatter_hold; @@ -190,8 +190,6 @@ static ssize_t sg_new_write(Sg_fd *sfp, struct file *file, int read_only, Sg_request **o_srp); static int sg_common_write(Sg_fd * sfp, Sg_request * srp, unsigned char *cmnd, int timeout, int blocking); -static int sg_u_iovec(sg_io_hdr_t * hp, int sg_num, int ind, - int wr_xf, int *countp, unsigned char __user **up); static int sg_write_xfer(Sg_request * srp); static int sg_read_xfer(Sg_request * srp); static int sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer); @@ -199,8 +197,6 @@ static void sg_remove_scat(Sg_scatter_hold * schp); static void sg_build_reserve(Sg_fd * sfp, int req_size); static void sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size); static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp); -static struct page *sg_page_malloc(int rqSz, int lowDma, int *retSzp); -static void sg_page_free(struct page *page, int size); static Sg_fd *sg_add_sfp(Sg_device * sdp, int dev); static int sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp); static void __sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp); @@ -771,26 +767,11 @@ sg_common_write(Sg_fd * sfp, Sg_request * srp, break; } hp->duration = jiffies_to_msecs(jiffies); -/* Now send everything of to mid-level. The next time we hear about this - packet is when sg_cmd_done() is called (i.e. a callback). */ - if (srp->rq) { - srp->rq->timeout = timeout; - blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk, - srp->rq, 1, sg_rq_end_io); - return 0; - } - if (scsi_execute_async(sdp->device, cmnd, hp->cmd_len, data_dir, srp->data.buffer, - hp->dxfer_len, srp->data.k_use_sg, timeout, - SG_DEFAULT_RETRIES, srp, sg_cmd_done, - GFP_ATOMIC)) { - SCSI_LOG_TIMEOUT(1, printk("sg_common_write: scsi_execute_async failed\n")); - /* - * most likely out of mem, but could also be a bad map - */ - sg_finish_rem_req(srp); - return -ENOMEM; - } else - return 0; + + srp->rq->timeout = timeout; + blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk, + srp->rq, 1, sg_rq_end_io); + return 0; } static int @@ -1206,8 +1187,7 @@ sg_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf) Sg_fd *sfp; unsigned long offset, len, sa; Sg_scatter_hold *rsv_schp; - struct scatterlist *sg; - int k; + int k, length; if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data))) return VM_FAULT_SIGBUS; @@ -1217,15 +1197,14 @@ sg_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf) return VM_FAULT_SIGBUS; SCSI_LOG_TIMEOUT(3, printk("sg_vma_fault: offset=%lu, scatg=%d\n", offset, rsv_schp->k_use_sg)); - sg = rsv_schp->buffer; sa = vma->vm_start; - for (k = 0; (k < rsv_schp->k_use_sg) && (sa < vma->vm_end); - ++k, sg = sg_next(sg)) { + length = 1 << (PAGE_SHIFT + rsv_schp->page_order); + for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) { len = vma->vm_end - sa; - len = (len < sg->length) ? len : sg->length; + len = (len < length) ? len : length; if (offset < len) { - struct page *page; - page = virt_to_page(page_address(sg_page(sg)) + offset); + struct page *page = nth_page(rsv_schp->pages[k], + offset >> PAGE_SHIFT); get_page(page); /* increment page count */ vmf->page = page; return 0; /* success */ @@ -1247,8 +1226,7 @@ sg_mmap(struct file *filp, struct vm_area_struct *vma) Sg_fd *sfp; unsigned long req_sz, len, sa; Sg_scatter_hold *rsv_schp; - int k; - struct scatterlist *sg; + int k, length; if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data))) return -ENXIO; @@ -1262,11 +1240,10 @@ sg_mmap(struct file *filp, struct vm_area_struct *vma) return -ENOMEM; /* cannot map more than reserved buffer */ sa = vma->vm_start; - sg = rsv_schp->buffer; - for (k = 0; (k < rsv_schp->k_use_sg) && (sa < vma->vm_end); - ++k, sg = sg_next(sg)) { + length = 1 << (PAGE_SHIFT + rsv_schp->page_order); + for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) { len = vma->vm_end - sa; - len = (len < sg->length) ? len : sg->length; + len = (len < length) ? len : length; sa += len; } @@ -1310,7 +1287,6 @@ sg_cmd_done(void *data, char *sense, int result, int resid) if (0 != result) { struct scsi_sense_hdr sshdr; - memcpy(srp->sense_b, sense, sizeof (srp->sense_b)); srp->header.status = 0xff & result; srp->header.masked_status = status_byte(result); srp->header.msg_status = msg_byte(result); @@ -1685,34 +1661,51 @@ static int sg_start_req(Sg_request *srp, unsigned char *cmd) Sg_scatter_hold *rsv_schp = &sfp->reserve; struct request_queue *q = sfp->parentdp->device->request_queue; unsigned long alignment = queue_dma_alignment(q) | q->dma_pad_mask; + struct rq_map_data map_data; SCSI_LOG_TIMEOUT(4, printk("sg_start_req: dxfer_len=%d\n", dxfer_len)); + res = __sg_start_req(srp, hp, cmd); + if (res) + return res; + if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE)) - return __sg_start_req(srp, hp, cmd); + return 0; #ifdef SG_ALLOW_DIO_CODE if (sg_allow_dio && (hp->flags & SG_FLAG_DIRECT_IO) && (dxfer_dir != SG_DXFER_UNKNOWN) && (0 == hp->iovec_count) && (!sfp->parentdp->device->host->unchecked_isa_dma) && - !(uaddr & alignment) && !(dxfer_len & alignment)) { - res = __sg_start_req(srp, hp, cmd); - if (!res) - res = sg_build_direct(srp, sfp, dxfer_len); - - return res; - } + !(uaddr & alignment) && !(dxfer_len & alignment)) + return sg_build_direct(srp, sfp, dxfer_len); #endif if ((!sg_res_in_use(sfp)) && (dxfer_len <= rsv_schp->bufflen)) sg_link_reserve(sfp, srp, dxfer_len); - else { + else res = sg_build_indirect(req_schp, sfp, dxfer_len); - if (res) { - sg_remove_scat(req_schp); - return res; - } + + if (!res) { + struct request *rq = srp->rq; + Sg_scatter_hold *schp = &srp->data; + int iovec_count = (int) hp->iovec_count; + + map_data.pages = schp->pages; + map_data.page_order = schp->page_order; + map_data.nr_entries = schp->k_use_sg; + + if (iovec_count) + res = blk_rq_map_user_iov(q, rq, &map_data, hp->dxferp, + iovec_count, + hp->dxfer_len, GFP_ATOMIC); + else + res = blk_rq_map_user(q, rq, &map_data, hp->dxferp, + hp->dxfer_len, GFP_ATOMIC); + + if (!res) + srp->bio = rq->bio; } - return 0; + + return res; } static void @@ -1730,6 +1723,7 @@ sg_finish_rem_req(Sg_request * srp) if (srp->rq) { if (srp->bio) blk_rq_unmap_user(srp->bio); + blk_put_request(srp->rq); } @@ -1739,21 +1733,12 @@ sg_finish_rem_req(Sg_request * srp) static int sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize) { - int sg_bufflen = tablesize * sizeof(struct scatterlist); + int sg_bufflen = tablesize * sizeof(struct page *); gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN; - /* - * TODO: test without low_dma, we should not need it since - * the block layer will bounce the buffer for us - * - * XXX(hch): we shouldn't need GFP_DMA for the actual S/G list. - */ - if (sfp->low_dma) - gfp_flags |= GFP_DMA; - schp->buffer = kzalloc(sg_bufflen, gfp_flags); - if (!schp->buffer) + schp->pages = kzalloc(sg_bufflen, gfp_flags); + if (!schp->pages) return -ENOMEM; - sg_init_table(schp->buffer, tablesize); schp->sglist_len = sg_bufflen; return tablesize; /* number of scat_gath elements allocated */ } @@ -1780,11 +1765,10 @@ sg_build_direct(Sg_request * srp, Sg_fd * sfp, int dxfer_len) static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size) { - struct scatterlist *sg; - int ret_sz = 0, k, rem_sz, num, mx_sc_elems; + int ret_sz = 0, i, k, rem_sz, num, mx_sc_elems; int sg_tablesize = sfp->parentdp->sg_tablesize; - int blk_size = buff_size; - struct page *p = NULL; + int blk_size = buff_size, order; + gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN; if (blk_size < 0) return -EFAULT; @@ -1808,15 +1792,26 @@ sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_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 = sg_next(sg)) { - + + if (sfp->low_dma) + gfp_mask |= GFP_DMA; + + if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO)) + gfp_mask |= __GFP_ZERO; + + order = get_order(num); +retry: + ret_sz = 1 << (PAGE_SHIFT + order); + + for (k = 0, rem_sz = blk_size; rem_sz > 0 && k < mx_sc_elems; + k++, rem_sz -= ret_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; + scatter_elem_sz_prev : rem_sz; + + schp->pages[k] = alloc_pages(gfp_mask, order); + if (!schp->pages[k]) + goto out; if (num == scatter_elem_sz_prev) { if (unlikely(ret_sz > scatter_elem_sz_prev)) { @@ -1824,12 +1819,12 @@ sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size) scatter_elem_sz_prev = ret_sz; } } - sg_set_page(sg, p, (ret_sz > num) ? num : ret_sz, 0); SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k=%d, num=%d, " "ret_sz=%d\n", k, num, ret_sz)); } /* end of for loop */ + schp->page_order = order; schp->k_use_sg = k; SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k_use_sg=%d, " "rem_sz=%d\n", k, rem_sz)); @@ -1837,8 +1832,15 @@ sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size) schp->bufflen = blk_size; if (rem_sz > 0) /* must have failed */ return -ENOMEM; - return 0; +out: + for (i = 0; i < k; i++) + __free_pages(schp->pages[k], order); + + if (--order >= 0) + goto retry; + + return -ENOMEM; } static int @@ -1846,13 +1848,8 @@ sg_write_xfer(Sg_request * srp) { sg_io_hdr_t *hp = &srp->header; Sg_scatter_hold *schp = &srp->data; - struct scatterlist *sg = schp->buffer; int num_xfer = 0; - int j, k, onum, usglen, ksglen, res; - int iovec_count = (int) hp->iovec_count; int dxfer_dir = hp->dxfer_direction; - unsigned char *p; - unsigned char __user *up; int new_interface = ('\0' == hp->interface_id) ? 0 : 1; if ((SG_DXFER_UNKNOWN == dxfer_dir) || (SG_DXFER_TO_DEV == dxfer_dir) || @@ -1866,83 +1863,9 @@ sg_write_xfer(Sg_request * srp) && ((SG_FLAG_NO_DXFER | SG_FLAG_MMAP_IO) & hp->flags))) return 0; - SCSI_LOG_TIMEOUT(4, printk("sg_write_xfer: num_xfer=%d, iovec_count=%d, k_use_sg=%d\n", - num_xfer, iovec_count, schp->k_use_sg)); - if (iovec_count) { - onum = iovec_count; - if (!access_ok(VERIFY_READ, hp->dxferp, SZ_SG_IOVEC * onum)) - return -EFAULT; - } else - onum = 1; + SCSI_LOG_TIMEOUT(4, printk("sg_write_xfer: num_xfer=%d, k_use_sg=%d\n", + num_xfer, schp->k_use_sg)); - ksglen = sg->length; - p = page_address(sg_page(sg)); - for (j = 0, k = 0; j < onum; ++j) { - res = sg_u_iovec(hp, iovec_count, j, 1, &usglen, &up); - if (res) - return res; - - for (; p; sg = sg_next(sg), ksglen = sg->length, - p = page_address(sg_page(sg))) { - if (usglen <= 0) - break; - if (ksglen > usglen) { - if (usglen >= num_xfer) { - if (__copy_from_user(p, up, num_xfer)) - return -EFAULT; - return 0; - } - if (__copy_from_user(p, up, usglen)) - return -EFAULT; - p += usglen; - ksglen -= usglen; - break; - } else { - if (ksglen >= num_xfer) { - if (__copy_from_user(p, up, num_xfer)) - return -EFAULT; - return 0; - } - if (__copy_from_user(p, up, ksglen)) - return -EFAULT; - up += ksglen; - usglen -= ksglen; - } - ++k; - if (k >= schp->k_use_sg) - return 0; - } - } - - return 0; -} - -static int -sg_u_iovec(sg_io_hdr_t * hp, int sg_num, int ind, - int wr_xf, int *countp, unsigned char __user **up) -{ - int num_xfer = (int) hp->dxfer_len; - unsigned char __user *p = hp->dxferp; - int count; - - if (0 == sg_num) { - if (wr_xf && ('\0' == hp->interface_id)) - count = (int) hp->flags; /* holds "old" input_size */ - else - count = num_xfer; - } else { - sg_iovec_t iovec; - if (__copy_from_user(&iovec, p + ind*SZ_SG_IOVEC, SZ_SG_IOVEC)) - return -EFAULT; - p = iovec.iov_base; - count = (int) iovec.iov_len; - } - if (!access_ok(wr_xf ? VERIFY_READ : VERIFY_WRITE, p, count)) - return -EFAULT; - if (up) - *up = p; - if (countp) - *countp = count; return 0; } @@ -1950,21 +1873,18 @@ static void sg_remove_scat(Sg_scatter_hold * schp) { SCSI_LOG_TIMEOUT(4, printk("sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg)); - if (schp->buffer && (schp->sglist_len > 0)) { - struct scatterlist *sg = schp->buffer; - + if (schp->pages && schp->sglist_len > 0) { if (!schp->dio_in_use) { int k; - for (k = 0; (k < schp->k_use_sg) && sg_page(sg); - ++k, sg = sg_next(sg)) { + for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) { SCSI_LOG_TIMEOUT(5, printk( - "sg_remove_scat: k=%d, pg=0x%p, len=%d\n", - k, sg_page(sg), sg->length)); - sg_page_free(sg_page(sg), sg->length); + "sg_remove_scat: k=%d, pg=0x%p\n", + k, schp->pages[k])); + __free_pages(schp->pages[k], schp->page_order); } - kfree(schp->buffer); + kfree(schp->pages); } } memset(schp, 0, sizeof (*schp)); @@ -1975,13 +1895,8 @@ sg_read_xfer(Sg_request * srp) { sg_io_hdr_t *hp = &srp->header; Sg_scatter_hold *schp = &srp->data; - struct scatterlist *sg = schp->buffer; int num_xfer = 0; - int j, k, onum, usglen, ksglen, res; - int iovec_count = (int) hp->iovec_count; int dxfer_dir = hp->dxfer_direction; - unsigned char *p; - unsigned char __user *up; int new_interface = ('\0' == hp->interface_id) ? 0 : 1; if ((SG_DXFER_UNKNOWN == dxfer_dir) || (SG_DXFER_FROM_DEV == dxfer_dir) @@ -1996,53 +1911,7 @@ sg_read_xfer(Sg_request * srp) return 0; SCSI_LOG_TIMEOUT(4, printk("sg_read_xfer: num_xfer=%d, iovec_count=%d, k_use_sg=%d\n", - num_xfer, iovec_count, schp->k_use_sg)); - if (iovec_count) { - onum = iovec_count; - if (!access_ok(VERIFY_READ, hp->dxferp, SZ_SG_IOVEC * onum)) - return -EFAULT; - } else - onum = 1; - - p = page_address(sg_page(sg)); - ksglen = sg->length; - for (j = 0, k = 0; j < onum; ++j) { - res = sg_u_iovec(hp, iovec_count, j, 0, &usglen, &up); - if (res) - return res; - - for (; p; sg = sg_next(sg), ksglen = sg->length, - p = page_address(sg_page(sg))) { - if (usglen <= 0) - break; - if (ksglen > usglen) { - if (usglen >= num_xfer) { - if (__copy_to_user(up, p, num_xfer)) - return -EFAULT; - return 0; - } - if (__copy_to_user(up, p, usglen)) - return -EFAULT; - p += usglen; - ksglen -= usglen; - break; - } else { - if (ksglen >= num_xfer) { - if (__copy_to_user(up, p, num_xfer)) - return -EFAULT; - return 0; - } - if (__copy_to_user(up, p, ksglen)) - return -EFAULT; - up += ksglen; - usglen -= ksglen; - } - ++k; - if (k >= schp->k_use_sg) - return 0; - } - } - + num_xfer, (int)hp->iovec_count, schp->k_use_sg)); return 0; } @@ -2050,7 +1919,6 @@ static int sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer) { Sg_scatter_hold *schp = &srp->data; - struct scatterlist *sg = schp->buffer; int k, num; SCSI_LOG_TIMEOUT(4, printk("sg_read_oxfer: num_read_xfer=%d\n", @@ -2058,15 +1926,18 @@ sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer) if ((!outp) || (num_read_xfer <= 0)) return 0; - for (k = 0; (k < schp->k_use_sg) && sg_page(sg); ++k, sg = sg_next(sg)) { - num = sg->length; + blk_rq_unmap_user(srp->bio); + srp->bio = NULL; + + num = 1 << (PAGE_SHIFT + schp->page_order); + for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) { if (num > num_read_xfer) { - if (__copy_to_user(outp, page_address(sg_page(sg)), + if (__copy_to_user(outp, page_address(schp->pages[k]), num_read_xfer)) return -EFAULT; break; } else { - if (__copy_to_user(outp, page_address(sg_page(sg)), + if (__copy_to_user(outp, page_address(schp->pages[k]), num)) return -EFAULT; num_read_xfer -= num; @@ -2101,24 +1972,22 @@ sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size) { Sg_scatter_hold *req_schp = &srp->data; Sg_scatter_hold *rsv_schp = &sfp->reserve; - struct scatterlist *sg = rsv_schp->buffer; int k, num, rem; srp->res_used = 1; SCSI_LOG_TIMEOUT(4, printk("sg_link_reserve: size=%d\n", size)); rem = size; - for (k = 0; k < rsv_schp->k_use_sg; ++k, sg = sg_next(sg)) { - num = sg->length; + num = 1 << (PAGE_SHIFT + rsv_schp->page_order); + for (k = 0; k < rsv_schp->k_use_sg; k++) { if (rem <= num) { - sfp->save_scat_len = num; - sg->length = rem; req_schp->k_use_sg = k + 1; req_schp->sglist_len = rsv_schp->sglist_len; - req_schp->buffer = rsv_schp->buffer; + req_schp->pages = rsv_schp->pages; req_schp->bufflen = size; req_schp->b_malloc_len = rsv_schp->b_malloc_len; + req_schp->page_order = rsv_schp->page_order; break; } else rem -= num; @@ -2132,22 +2001,13 @@ static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp) { Sg_scatter_hold *req_schp = &srp->data; - Sg_scatter_hold *rsv_schp = &sfp->reserve; SCSI_LOG_TIMEOUT(4, printk("sg_unlink_reserve: req->k_use_sg=%d\n", (int) req_schp->k_use_sg)); - if ((rsv_schp->k_use_sg > 0) && (req_schp->k_use_sg > 0)) { - struct scatterlist *sg = rsv_schp->buffer; - - if (sfp->save_scat_len > 0) - (sg + (req_schp->k_use_sg - 1))->length = - (unsigned) sfp->save_scat_len; - else - SCSI_LOG_TIMEOUT(1, printk ("sg_unlink_reserve: BAD save_scat_len\n")); - } req_schp->k_use_sg = 0; req_schp->bufflen = 0; - req_schp->buffer = NULL; + req_schp->pages = NULL; + req_schp->page_order = 0; req_schp->sglist_len = 0; sfp->save_scat_len = 0; srp->res_used = 0; @@ -2405,53 +2265,6 @@ sg_res_in_use(Sg_fd * sfp) return srp ? 1 : 0; } -/* 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; - - if ((rqSz <= 0) || (NULL == retSzp)) - return resp; - - if (lowDma) - page_mask = GFP_ATOMIC | GFP_DMA | __GFP_COMP | __GFP_NOWARN; - else - page_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN; - - 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) { - --order; - a_size >>= 1; /* divide by 2, until PAGE_SIZE */ - resp = alloc_pages(page_mask, order); /* try half */ - resSz = a_size; - } - if (resp) { - if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO)) - memset(page_address(resp), 0, resSz); - *retSzp = resSz; - } - return resp; -} - -static void -sg_page_free(struct page *page, int size) -{ - int order, a_size; - - if (!page) - return; - for (order = 0, a_size = PAGE_SIZE; a_size < size; - order++, a_size <<= 1) ; - __free_pages(page, order); -} - #ifdef CONFIG_SCSI_PROC_FS static int sg_idr_max_id(int id, void *p, void *data)