Christoph Hellwig wrote:
On Thu, Sep 15, 2005 at 11:39:53PM -0500, Mike Christie wrote:
Convert sg to always use scatterlists.
I made the scsi api take scatterlists now so HighMem is supported
for DIO.
Looks pretty nice. There's lots of page_address() calls left, two
yeah I was going to change them to kmaps for Doug and Kai, but thought I
should do that in another patch in case I mees up. I thought in the
paths they use page_address are the indirect or mmap paths which
allocate the pages from GFP_KERNEL or GFP_DMA.
of them can be removed trivially and two were used to reimplement
a rather odd kzalloc. Also switch ->buffer to be a struct scatterlist *
Ok thanks. When I respin my patches, I will include this and I will send
a kmap patch to allow the ULDs to use HighMem in the non-DIO paths.
Index: linux-2.6/drivers/scsi/sg.c
===================================================================
--- linux-2.6.orig/drivers/scsi/sg.c 2005-09-16 11:15:43.000000000 +0200
+++ linux-2.6/drivers/scsi/sg.c 2005-09-16 11:23:43.000000000 +0200
@@ -120,7 +120,7 @@
unsigned short 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 */
- void *buffer; /* scatter list */
+ struct scatterlist *buffer;/* scatter list */
char dio_in_use; /* 0->indirect IO (or mmap), 1->dio */
unsigned char cmd_opcode; /* first byte of command */
} Sg_scatter_hold;
@@ -1148,7 +1148,6 @@
sg_rb_correct4mmap(Sg_scatter_hold * rsv_schp, int startFinish)
{
struct scatterlist *sg = rsv_schp->buffer;
- void *page_ptr;
struct page *page;
int k, m;
@@ -1158,7 +1157,6 @@
for (k = 0; k < rsv_schp->k_use_sg; ++k, ++sg) {
for (m = PAGE_SIZE; m < sg->length; m += PAGE_SIZE) {
page = sg->page;
- page_ptr = page_address(page) + m;
if (startFinish)
get_page(page);
else {
@@ -1174,7 +1172,6 @@
{
Sg_fd *sfp;
struct page *page = NOPAGE_SIGBUS;
- void *page_ptr = NULL;
unsigned long offset, len, sa;
Sg_scatter_hold *rsv_schp;
struct scatterlist *sg;
@@ -1196,7 +1193,6 @@
len = (len < sg->length) ? len : sg->length;
if (offset < len) {
page = sg->page;
- page_ptr = page_address(page) + offset;
get_page(page); /* increment page count */
break;
}
@@ -1689,26 +1685,22 @@
static int
sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
{
- int ret_sz;
- int elem_sz = sizeof (struct scatterlist);
- int sg_bufflen = tablesize * elem_sz;
- int mx_sc_elems = tablesize;
+ int sg_bufflen = tablesize * sizeof(struct scatterlist);
+ unsigned int 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.
*/
- schp->buffer = page_address(sg_page_malloc(sg_bufflen, sfp->low_dma,
- &ret_sz));
+ if (sfp->low_dma)
+ gfp_flags |= GFP_DMA;
+ schp->buffer = kzalloc(sg_bufflen, gfp_flags);
if (!schp->buffer)
return -ENOMEM;
- else if (ret_sz != sg_bufflen) {
- sg_bufflen = ret_sz;
- mx_sc_elems = sg_bufflen / elem_sz;
- }
schp->sglist_len = sg_bufflen;
- memset(schp->buffer, 0, sg_bufflen);
- return mx_sc_elems; /* number of scat_gath elements allocated */
+ return tablesize; /* number of scat_gath elements allocated */
}
#ifdef SG_ALLOW_DIO_CODE
@@ -2036,7 +2028,7 @@
sg_page_free(sg->page, sg->length);
}
}
- sg_page_free(virt_to_page(schp->buffer), schp->sglist_len);
+ kfree(schp->buffer);
}
memset(schp, 0, sizeof (*schp));
}
@@ -2353,16 +2345,13 @@
static Sg_fd *
sg_add_sfp(Sg_device * sdp, int dev)
{
- struct page *p;
Sg_fd *sfp;
unsigned long iflags;
- p = sg_page_malloc(sizeof (Sg_fd), 0, NULL);
- if (!p)
+ sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
+ if (!sfp)
return NULL;
- sfp = (Sg_fd *) page_address(p);
- memset(sfp, 0, sizeof (Sg_fd));
init_waitqueue_head(&sfp->read_wait);
rwlock_init(&sfp->rq_list_lock);
@@ -2419,7 +2408,7 @@
}
sfp->parentdp = NULL;
SCSI_LOG_TIMEOUT(6, printk("__sg_remove_sfp: sfp=0x%p\n", sfp));
- sg_page_free(virt_to_page(sfp), sizeof (Sg_fd));
+ kfree(sfp);
}
/* Returns 0 in normal case, 1 when detached and sdp object removed */
-
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