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sg: convert the indirect IO path to use the block layer

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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 <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Douglas Gilbert <dougg@torque.net>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
FUJITA Tomonori 2008-08-29 12:32:18 +02:00 committed by Jens Axboe
parent 6e5a30cba5
commit 10db10d144
1 changed files with 105 additions and 292 deletions
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397
drivers/scsi/sg.c
View file

@ -47,7 +47,6 @@ static int sg_version_num = 30534; /* 2 digits for each component */
#include <linux/seq_file.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/scatterlist.h>
#include <linux/blktrace_api.h>
#include <linux/smp_lock.h>
@ -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)