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| author | Jan Beulich <JBeulich@suse.com> | 2012-05-30 09:22:51 +0100 |
|---|---|---|
| committer | Jan Beulich <JBeulich@suse.com> | 2012-05-30 09:22:51 +0100 |
| commit | 74c5f66048beacfc53589e8dc878cfd8d216b3d1 (patch) | |
| tree | a6a9f101adf7d75d6f9ca03cd19ccb583f3954c4 /xen/common/grant_table.c | |
| parent | e26560a4b056dad6d85ffd9ebfad9565f210a9cc (diff) | |
| download | xen-74c5f66048beacfc53589e8dc878cfd8d216b3d1.tar.gz xen-74c5f66048beacfc53589e8dc878cfd8d216b3d1.tar.bz2 xen-74c5f66048beacfc53589e8dc878cfd8d216b3d1.zip | |
gnttab: mark maptrack free list tail with an explicit terminator
... instead of using the mutable current limit.
This also addresses an apparent off-by-one mistake when checking for
exhaustion of the maptrack table.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Andrew Thomas <andrew.thomas@oracle.com>
Committed-by: Keir Fraser <keir@xen.org>
Diffstat (limited to 'xen/common/grant_table.c')
| -rw-r--r-- | xen/common/grant_table.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c index 974d4f482c..5f40aa01c8 100644 --- a/xen/common/grant_table.c +++ b/xen/common/grant_table.c @@ -107,6 +107,8 @@ static unsigned inline int max_nr_maptrack_frames(void) return (max_nr_grant_frames * MAX_MAPTRACK_TO_GRANTS_RATIO); } +#define MAPTRACK_TAIL (~0u) + #define SHGNT_PER_PAGE_V1 (PAGE_SIZE / sizeof(grant_entry_v1_t)) #define shared_entry_v1(t, e) \ ((t)->shared_v1[(e)/SHGNT_PER_PAGE_V1][(e)%SHGNT_PER_PAGE_V1]) @@ -198,7 +200,7 @@ __get_maptrack_handle( struct grant_table *t) { unsigned int h; - if ( unlikely((h = t->maptrack_head) == (t->maptrack_limit - 1)) ) + if ( unlikely((h = t->maptrack_head) == MAPTRACK_TAIL) ) return -1; t->maptrack_head = maptrack_entry(t, h).ref; return h; @@ -239,8 +241,10 @@ get_maptrack_handle( new_mt_limit = lgt->maptrack_limit + MAPTRACK_PER_PAGE; - for ( i = lgt->maptrack_limit; i < new_mt_limit; i++ ) - new_mt[i % MAPTRACK_PER_PAGE].ref = i + 1; + for ( i = 1; i < MAPTRACK_PER_PAGE; i++ ) + new_mt[i - 1].ref = lgt->maptrack_limit + i; + new_mt[i - 1].ref = lgt->maptrack_head; + lgt->maptrack_head = lgt->maptrack_limit; lgt->maptrack[nr_frames] = new_mt; smp_wmb(); @@ -2577,9 +2581,10 @@ grant_table_create( if ( (t->maptrack[0] = alloc_xenheap_page()) == NULL ) goto no_mem_3; clear_page(t->maptrack[0]); - t->maptrack_limit = PAGE_SIZE / sizeof(struct grant_mapping); - for ( i = 0; i < t->maptrack_limit; i++ ) - t->maptrack[0][i].ref = i+1; + t->maptrack_limit = MAPTRACK_PER_PAGE; + for ( i = 1; i < MAPTRACK_PER_PAGE; i++ ) + t->maptrack[0][i - 1].ref = i; + t->maptrack[0][i - 1].ref = MAPTRACK_TAIL; /* Shared grant table. */ if ( (t->shared_raw = xzalloc_array(void *, max_nr_grant_frames)) == NULL ) |