Jan Beulich
2011-Apr-04 15:39 UTC
[Xen-devel] [PATCH] linux-2.6.18: cleanup to blkback and blktap
Remove unused/unneccessary fields of their pending_req_t structures,
and reduce the width of those structures'' nr_pages field.
Move loop-invariant grant table flags calculation out of loops (also
in scsiback).
Signed-off-by: Jan Beulich <jbeulich@novell.com>
--- a/drivers/xen/blkback/blkback.c
+++ b/drivers/xen/blkback/blkback.c
@@ -75,10 +75,9 @@ module_param(debug_lvl, int, 0644);
typedef struct {
blkif_t *blkif;
u64 id;
- int nr_pages;
atomic_t pendcnt;
+ unsigned short nr_pages;
unsigned short operation;
- int status;
struct list_head free_list;
} pending_req_t;
@@ -257,22 +256,24 @@ int blkif_schedule(void *arg)
static void __end_block_io_op(pending_req_t *pending_req, int error)
{
+ int status = BLKIF_RSP_OKAY;
+
/* An error fails the entire request. */
if ((pending_req->operation == BLKIF_OP_WRITE_BARRIER) &&
(error == -EOPNOTSUPP)) {
DPRINTK("blkback: write barrier op failed, not supported\n");
blkback_barrier(XBT_NIL, pending_req->blkif->be, 0);
- pending_req->status = BLKIF_RSP_EOPNOTSUPP;
+ status = BLKIF_RSP_EOPNOTSUPP;
} else if (error) {
DPRINTK("Buffer not up-to-date at end of operation, "
"error=%d\n", error);
- pending_req->status = BLKIF_RSP_ERROR;
+ status = BLKIF_RSP_ERROR;
}
if (atomic_dec_and_test(&pending_req->pendcnt)) {
fast_flush_area(pending_req);
make_response(pending_req->blkif, pending_req->id,
- pending_req->operation, pending_req->status);
+ pending_req->operation, status);
blkif_put(pending_req->blkif);
free_req(pending_req);
}
@@ -389,7 +390,6 @@ static void dispatch_rw_block_io(blkif_t
blkif_request_t *req,
pending_req_t *pending_req)
{
- extern void ll_rw_block(int rw, int nr, struct buffer_head * bhs[]);
struct gnttab_map_grant_ref map[BLKIF_MAX_SEGMENTS_PER_REQUEST];
struct phys_req preq;
struct {
@@ -397,6 +397,7 @@ static void dispatch_rw_block_io(blkif_t
} seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
unsigned int nseg;
struct bio *bio = NULL;
+ uint32_t flags;
int ret, i;
int operation;
@@ -430,12 +431,13 @@ static void dispatch_rw_block_io(blkif_t
pending_req->blkif = blkif;
pending_req->id = req->id;
pending_req->operation = req->operation;
- pending_req->status = BLKIF_RSP_OKAY;
pending_req->nr_pages = nseg;
- for (i = 0; i < nseg; i++) {
- uint32_t flags;
+ flags = GNTMAP_host_map;
+ if (operation != READ)
+ flags |= GNTMAP_readonly;
+ for (i = 0; i < nseg; i++) {
seg[i].nsec = req->seg[i].last_sect -
req->seg[i].first_sect + 1;
@@ -444,9 +446,6 @@ static void dispatch_rw_block_io(blkif_t
goto fail_response;
preq.nr_sects += seg[i].nsec;
- flags = GNTMAP_host_map;
- if (operation != READ)
- flags |= GNTMAP_readonly;
gnttab_set_map_op(&map[i], vaddr(pending_req, i), flags,
req->seg[i].gref, blkif->domid);
}
--- a/drivers/xen/blktap/blktap.c
+++ b/drivers/xen/blktap/blktap.c
@@ -136,20 +136,14 @@ module_param(debug_lvl, int, 0644);
/*
* Each outstanding request that we''ve passed to the lower device
layers has a
- * ''pending_req'' allocated to it. Each buffer_head that
completes decrements
- * the pendcnt towards zero. When it hits zero, the specified domain has a
- * response queued for it, with the saved ''id'' passed back.
+ * ''pending_req'' allocated to it.
*/
typedef struct {
blkif_t *blkif;
u64 id;
unsigned short mem_idx;
- int nr_pages;
- atomic_t pendcnt;
- unsigned short operation;
- int status;
+ unsigned short nr_pages;
struct list_head free_list;
- int inuse;
} pending_req_t;
static pending_req_t *pending_reqs[MAX_PENDING_REQS];
@@ -996,10 +990,8 @@ static pending_req_t* alloc_req(void)
list_del(&req->free_list);
}
- if (req) {
- req->inuse = 1;
+ if (req)
alloc_pending_reqs++;
- }
spin_unlock_irqrestore(&pending_free_lock, flags);
return req;
@@ -1013,7 +1005,6 @@ static void free_req(pending_req_t *req)
spin_lock_irqsave(&pending_free_lock, flags);
alloc_pending_reqs--;
- req->inuse = 0;
if (mmap_lock && (req->mem_idx == mmap_alloc-1)) {
mmap_inuse--;
if (mmap_inuse == 0) mmap_req_del(mmap_alloc-1);
@@ -1415,16 +1406,15 @@ static void dispatch_rw_block_io(blkif_t
blkif_request_t *req,
pending_req_t *pending_req)
{
- extern void ll_rw_block(int rw, int nr, struct buffer_head * bhs[]);
- int op, operation = (req->operation == BLKIF_OP_WRITE) ? WRITE : READ;
struct gnttab_map_grant_ref map[BLKIF_MAX_SEGMENTS_PER_REQUEST*2];
unsigned int nseg;
- int ret, i, nr_sects = 0;
+ int ret, i, op, nr_sects = 0;
tap_blkif_t *info;
blkif_request_t *target;
unsigned int mmap_idx = pending_req->mem_idx;
unsigned int pending_idx = RTN_PEND_IDX(pending_req, mmap_idx);
unsigned int usr_idx;
+ uint32_t flags;
struct mm_struct *mm;
struct vm_area_struct *vma = NULL;
@@ -1467,9 +1457,11 @@ static void dispatch_rw_block_io(blkif_t
pending_req->blkif = blkif;
pending_req->id = req->id;
- pending_req->operation = operation;
- pending_req->status = BLKIF_RSP_OKAY;
pending_req->nr_pages = nseg;
+
+ flags = GNTMAP_host_map;
+ if (req->operation == BLKIF_OP_WRITE)
+ flags |= GNTMAP_readonly;
op = 0;
mm = info->mm;
if (!xen_feature(XENFEAT_auto_translated_physmap))
@@ -1478,14 +1470,10 @@ static void dispatch_rw_block_io(blkif_t
unsigned long uvaddr;
unsigned long kvaddr;
uint64_t ptep;
- uint32_t flags;
uvaddr = MMAP_VADDR(info->user_vstart, usr_idx, i);
kvaddr = idx_to_kaddr(mmap_idx, pending_idx, i);
- flags = GNTMAP_host_map;
- if (operation == WRITE)
- flags |= GNTMAP_readonly;
gnttab_set_map_op(&map[op], kvaddr, flags,
req->seg[i].gref, blkif->domid);
op++;
@@ -1499,11 +1487,9 @@ static void dispatch_rw_block_io(blkif_t
goto fail_flush;
}
- flags = GNTMAP_host_map | GNTMAP_application_map
- | GNTMAP_contains_pte;
- if (operation == WRITE)
- flags |= GNTMAP_readonly;
- gnttab_set_map_op(&map[op], ptep, flags,
+ gnttab_set_map_op(&map[op], ptep,
+ flags | GNTMAP_application_map
+ | GNTMAP_contains_pte,
req->seg[i].gref, blkif->domid);
op++;
}
@@ -1633,10 +1619,14 @@ static void dispatch_rw_block_io(blkif_t
wmb(); /* blktap_poll() reads req_prod_pvt asynchronously */
info->ufe_ring.req_prod_pvt++;
- if (operation == READ)
+ switch (req->operation) {
+ case BLKIF_OP_READ:
blkif->st_rd_sect += nr_sects;
- else if (operation == WRITE)
+ break;
+ case BLKIF_OP_WRITE:
blkif->st_wr_sect += nr_sects;
+ break;
+ }
return;
--- a/drivers/xen/scsiback/scsiback.c
+++ b/drivers/xen/scsiback/scsiback.c
@@ -274,14 +274,14 @@ static int scsiback_gnttab_data_map(vscs
return -ENOMEM;
}
- for (i = 0; i < nr_segments; i++) {
- flags = GNTMAP_host_map;
- if (write)
- flags |= GNTMAP_readonly;
+ flags = GNTMAP_host_map;
+ if (write)
+ flags |= GNTMAP_readonly;
+
+ for (i = 0; i < nr_segments; i++)
gnttab_set_map_op(&map[i], vaddr(pending_req, i), flags,
ring_req->seg[i].gref,
info->domid);
- }
err = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map, nr_segments);
BUG_ON(err);
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Daniel Stodden
2011-Apr-04 23:13 UTC
Re: [Xen-devel] [PATCH] linux-2.6.18: cleanup to blkback and blktap
On Mon, 2011-04-04 at 11:39 -0400, Jan Beulich wrote:> Remove unused/unneccessary fields of their pending_req_t structures, > and reduce the width of those structures'' nr_pages field. > > Move loop-invariant grant table flags calculation out of loops (also > in scsiback). > > Signed-off-by: Jan Beulich <jbeulich@novell.com>Ack, but just been looking. Regarding blktap, 2.6.32 and later even looks similar regarding the pending_req_t (now blktap_request). Daniel _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel