# HG changeset patch
# User Jan Beulich <jbeulich@xxxxxxxxxx>
# Date 1297328764 0
# Node ID 1128f2a18acfd4e8d0a7aad38afd107894399822
# Parent 350c17abbc171cff0227b4ee9131f32851ea4f37
blktap: a small fix and assorted cleanup
The main cleanup item is to convert the index map from a plain
"unsigned long" holding two merged together integers into a proper
structure (at once halving its size on 64-bit).
Additionally, add a previously missing range check of res.id in
blktap_read_ufe_ring() and remove blkif_reqs (which could have been
set via module load option to a value other than the default, which
code elsewhere isn't capable of handling).
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
---
drivers/xen/blktap/blktap.c | 151 +++++++++++++++++++-------------------------
1 files changed, 68 insertions(+), 83 deletions(-)
diff -r 350c17abbc17 -r 1128f2a18acf drivers/xen/blktap/blktap.c
--- a/drivers/xen/blktap/blktap.c Wed Feb 09 08:59:29 2011 +0000
+++ b/drivers/xen/blktap/blktap.c Thu Feb 10 09:06:04 2011 +0000
@@ -78,7 +78,6 @@
(_start + \
((_req) * BLKIF_MAX_SEGMENTS_PER_REQUEST * PAGE_SIZE) + \
((_seg) * PAGE_SIZE))
-static int blkif_reqs = MAX_PENDING_REQS;
static int mmap_pages = MMAP_PAGES;
#define RING_PAGES 1 /* BLKTAP - immediately before the mmap area, we
@@ -112,7 +111,9 @@ typedef struct tap_blkif {
pid_t pid; /*tapdisk process id */
enum { RUNNING, CLEANSHUTDOWN } status; /*Detect a clean userspace
shutdown */
- unsigned long *idx_map; /*Record the user ring id to kern
+ struct idx_map {
+ u16 mem, req;
+ } *idx_map; /*Record the user ring id to kern
[req id, idx] tuple */
blkif_t *blkif; /*Associate blkif with tapdev */
struct domid_translate_ext trans; /*Translation from domid to bus. */
@@ -122,7 +123,6 @@ static struct tap_blkif *tapfds[MAX_TAP_
static struct tap_blkif *tapfds[MAX_TAP_DEV];
static int blktap_next_minor;
-module_param(blkif_reqs, int, 0);
/* Run-time switchable: /sys/module/blktap/parameters/ */
static unsigned int log_stats = 0;
static unsigned int debug_lvl = 0;
@@ -153,12 +153,6 @@ static DECLARE_WAIT_QUEUE_HEAD (pending_
static DECLARE_WAIT_QUEUE_HEAD (pending_free_wq);
static int alloc_pending_reqs;
-typedef unsigned int PEND_RING_IDX;
-
-static inline int MASK_PEND_IDX(int i) {
- return (i & (MAX_PENDING_REQS-1));
-}
-
static inline unsigned int RTN_PEND_IDX(pending_req_t *req, int idx) {
return (req - pending_reqs[idx]);
}
@@ -248,40 +242,26 @@ static inline int BLKTAP_MODE_VALID(unsi
* ring ID.
*/
-static inline unsigned long MAKE_ID(domid_t fe_dom, PEND_RING_IDX idx)
-{
- return ((fe_dom << 16) | MASK_PEND_IDX(idx));
-}
-
-extern inline PEND_RING_IDX ID_TO_IDX(unsigned long id)
-{
- return (PEND_RING_IDX)(id & 0x0000ffff);
-}
-
-extern inline int ID_TO_MIDX(unsigned long id)
-{
- return (int)(id >> 16);
-}
-
-#define INVALID_REQ 0xdead0000
+#define INVALID_MIDX 0xdead
/*TODO: Convert to a free list*/
-static inline int GET_NEXT_REQ(unsigned long *idx_map)
-{
- int i;
+static inline unsigned int GET_NEXT_REQ(const struct idx_map *idx_map)
+{
+ unsigned int i;
+
for (i = 0; i < MAX_PENDING_REQS; i++)
- if (idx_map[i] == INVALID_REQ)
- return i;
-
- return INVALID_REQ;
-}
-
-static inline int OFFSET_TO_USR_IDX(int offset)
+ if (idx_map[i].mem == INVALID_MIDX)
+ break;
+
+ return i;
+}
+
+static inline unsigned int OFFSET_TO_USR_IDX(unsigned long offset)
{
return offset / BLKIF_MAX_SEGMENTS_PER_REQUEST;
}
-static inline int OFFSET_TO_SEG(int offset)
+static inline unsigned int OFFSET_TO_SEG(unsigned long offset)
{
return offset % BLKIF_MAX_SEGMENTS_PER_REQUEST;
}
@@ -318,13 +298,11 @@ static pte_t blktap_clear_pte(struct vm_
{
pte_t copy;
tap_blkif_t *info = NULL;
- int offset, seg, usr_idx, pending_idx, mmap_idx;
- unsigned long uvstart = 0;
- unsigned long kvaddr;
+ unsigned int seg, usr_idx, pending_idx, mmap_idx, count = 0;
+ unsigned long offset, uvstart = 0;
struct page *pg;
struct grant_handle_pair *khandle;
struct gnttab_unmap_grant_ref unmap[2];
- int count = 0;
/*
* If the address is before the start of the grant mapped region or
@@ -342,14 +320,13 @@ static pte_t blktap_clear_pte(struct vm_
BUG_ON(!info);
BUG_ON(!info->idx_map);
- offset = (int) ((uvaddr - uvstart) >> PAGE_SHIFT);
+ offset = (uvaddr - uvstart) >> PAGE_SHIFT;
usr_idx = OFFSET_TO_USR_IDX(offset);
seg = OFFSET_TO_SEG(offset);
- pending_idx = MASK_PEND_IDX(ID_TO_IDX(info->idx_map[usr_idx]));
- mmap_idx = ID_TO_MIDX(info->idx_map[usr_idx]);
-
- kvaddr = idx_to_kaddr(mmap_idx, pending_idx, seg);
+ pending_idx = info->idx_map[usr_idx].req;
+ mmap_idx = info->idx_map[usr_idx].mem;
+
pg = idx_to_page(mmap_idx, pending_idx, seg);
ClearPageReserved(pg);
info->foreign_map.map[offset + RING_PAGES] = NULL;
@@ -357,12 +334,14 @@ static pte_t blktap_clear_pte(struct vm_
khandle = &pending_handle(mmap_idx, pending_idx, seg);
if (khandle->kernel != INVALID_GRANT_HANDLE) {
- gnttab_set_unmap_op(&unmap[count], kvaddr,
+ unsigned long pfn = page_to_pfn(pg);
+
+ gnttab_set_unmap_op(&unmap[count],
+ (unsigned long)pfn_to_kaddr(pfn),
GNTMAP_host_map, khandle->kernel);
count++;
- set_phys_to_machine(__pa(kvaddr) >> PAGE_SHIFT,
- INVALID_P2M_ENTRY);
+ set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
}
if (khandle->user != INVALID_GRANT_HANDLE) {
@@ -621,7 +600,7 @@ static int blktap_open(struct inode *ino
filp->private_data = info;
info->mm = NULL;
- info->idx_map = kmalloc(sizeof(unsigned long) * MAX_PENDING_REQS,
+ info->idx_map = kmalloc(sizeof(*info->idx_map) * MAX_PENDING_REQS,
GFP_KERNEL);
if (info->idx_map == NULL)
@@ -629,8 +608,10 @@ static int blktap_open(struct inode *ino
if (idx > 0) {
init_waitqueue_head(&info->wait);
- for (i = 0; i < MAX_PENDING_REQS; i++)
- info->idx_map[i] = INVALID_REQ;
+ for (i = 0; i < MAX_PENDING_REQS; i++) {
+ info->idx_map[i].mem = INVALID_MIDX;
+ info->idx_map[i].req = ~0;
+ }
}
DPRINTK("Tap open: device /dev/xen/blktap%d\n",idx);
@@ -887,11 +868,9 @@ static int blktap_ioctl(struct inode *in
return blktap_major;
case BLKTAP_QUERY_ALLOC_REQS:
- {
- WPRINTK("BLKTAP_QUERY_ALLOC_REQS ioctl: %d/%d\n",
- alloc_pending_reqs, blkif_reqs);
- return (alloc_pending_reqs/blkif_reqs) * 100;
- }
+ WPRINTK("BLKTAP_QUERY_ALLOC_REQS ioctl: %d/%lu\n",
+ alloc_pending_reqs, MAX_PENDING_REQS);
+ return (alloc_pending_reqs/MAX_PENDING_REQS) * 100;
}
return -ENOIOCTLCMD;
}
@@ -946,14 +925,14 @@ static int req_increase(void)
return -EINVAL;
pending_reqs[mmap_alloc] = kzalloc(sizeof(pending_req_t)
- * blkif_reqs, GFP_KERNEL);
+ * MAX_PENDING_REQS, GFP_KERNEL);
foreign_pages[mmap_alloc] = alloc_empty_pages_and_pagevec(mmap_pages);
if (!pending_reqs[mmap_alloc] || !foreign_pages[mmap_alloc])
goto out_of_memory;
- DPRINTK("%s: reqs=%d, pages=%d\n",
- __FUNCTION__, blkif_reqs, mmap_pages);
+ DPRINTK("%s: reqs=%lu, pages=%d\n",
+ __FUNCTION__, MAX_PENDING_REQS, mmap_pages);
for (i = 0; i < MAX_PENDING_REQS; i++) {
list_add_tail(&pending_reqs[mmap_alloc][i].free_list,
@@ -1053,14 +1032,14 @@ static void blktap_zap_page_range(struct
}
}
-static void fast_flush_area(pending_req_t *req, int k_idx, int u_idx,
- int tapidx)
+static void fast_flush_area(pending_req_t *req, unsigned int k_idx,
+ unsigned int u_idx, int tapidx)
{
struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST*2];
- unsigned int i, invcount = 0, locked = 0;
+ unsigned int i, mmap_idx, invcount = 0, locked = 0;
struct grant_handle_pair *khandle;
uint64_t ptep;
- int ret, mmap_idx;
+ int ret;
unsigned long uvaddr;
tap_blkif_t *info;
struct mm_struct *mm;
@@ -1215,7 +1194,7 @@ static int blktap_read_ufe_ring(tap_blki
RING_IDX i, j, rp;
blkif_response_t *resp;
blkif_t *blkif=NULL;
- int pending_idx, usr_idx, mmap_idx;
+ unsigned int pending_idx, usr_idx, mmap_idx;
pending_req_t *pending_req;
if (!info)
@@ -1237,18 +1216,23 @@ static int blktap_read_ufe_ring(tap_blki
++info->ufe_ring.rsp_cons;
/*retrieve [usr_idx] to [mmap_idx,pending_idx] mapping*/
- usr_idx = (int)res.id;
- pending_idx = MASK_PEND_IDX(ID_TO_IDX(info->idx_map[usr_idx]));
- mmap_idx = ID_TO_MIDX(info->idx_map[usr_idx]);
-
- if ( (mmap_idx >= mmap_alloc) ||
- (ID_TO_IDX(info->idx_map[usr_idx]) >= MAX_PENDING_REQS) )
- WPRINTK("Incorrect req map"
- "[%d], internal map [%d,%d (%d)]\n",
- usr_idx, mmap_idx,
- ID_TO_IDX(info->idx_map[usr_idx]),
- MASK_PEND_IDX(
- ID_TO_IDX(info->idx_map[usr_idx])));
+ if (res.id >= MAX_PENDING_REQS) {
+ WPRINTK("incorrect req map [%llx]\n",
+ (unsigned long long)res.id);
+ continue;
+ }
+
+ usr_idx = (unsigned int)res.id;
+ pending_idx = info->idx_map[usr_idx].req;
+ mmap_idx = info->idx_map[usr_idx].mem;
+
+ if (mmap_idx >= mmap_alloc ||
+ pending_idx >= MAX_PENDING_REQS) {
+ WPRINTK("incorrect req map [%d],"
+ " internal map [%d,%d]\n",
+ usr_idx, mmap_idx, pending_idx);
+ continue;
+ }
pending_req = &pending_reqs[mmap_idx][pending_idx];
blkif = pending_req->blkif;
@@ -1267,7 +1251,7 @@ static int blktap_read_ufe_ring(tap_blki
info->foreign_map.map[offset] = NULL;
}
fast_flush_area(pending_req, pending_idx, usr_idx, info->minor);
- info->idx_map[usr_idx] = INVALID_REQ;
+ info->idx_map[usr_idx].mem = INVALID_MIDX;
make_response(blkif, pending_req->id, res.operation,
res.status);
blkif_put(pending_req->blkif);
@@ -1423,9 +1407,9 @@ static void dispatch_rw_block_io(blkif_t
int ret, i, nr_sects = 0;
tap_blkif_t *info;
blkif_request_t *target;
- int pending_idx = RTN_PEND_IDX(pending_req,pending_req->mem_idx);
- int usr_idx;
- uint16_t mmap_idx = pending_req->mem_idx;
+ unsigned int mmap_idx = pending_req->mem_idx;
+ unsigned int pending_idx = RTN_PEND_IDX(pending_req, mmap_idx);
+ unsigned int usr_idx;
struct mm_struct *mm;
struct vm_area_struct *vma = NULL;
@@ -1438,8 +1422,8 @@ static void dispatch_rw_block_io(blkif_t
/* Check we have space on user ring - should never fail. */
usr_idx = GET_NEXT_REQ(info->idx_map);
- if (usr_idx == INVALID_REQ) {
- BUG();
+ if (usr_idx >= MAX_PENDING_REQS) {
+ WARN_ON(1);
goto fail_response;
}
@@ -1622,7 +1606,8 @@ static void dispatch_rw_block_io(blkif_t
up_write(&mm->mmap_sem);
/*record [mmap_idx,pending_idx] to [usr_idx] mapping*/
- info->idx_map[usr_idx] = MAKE_ID(mmap_idx, pending_idx);
+ info->idx_map[usr_idx].mem = mmap_idx;
+ info->idx_map[usr_idx].req = pending_idx;
blkif_get(blkif);
/* Finally, write the request message to the user ring. */
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