[PATCH v3 2/2] pack-objects: merge read_lock and lock in packing_data struct

[Patrick Hogg <phogg@xxxxxxxxxxxx>]

Upgrade the packing_data lock to a recursive mutex to make it suitable
for current read_lock usages. Additionally remove the superfluous
#ifndef NO_PTHREADS guard around mutex initialization in
prepare_packing_data as the mutex functions themselves are already
protected.

Signed-off-by: Patrick Hogg <phogg@xxxxxxxxxxxx>
---
 builtin/pack-objects.c | 24 ++++++++++++------------
 pack-objects.c         |  5 +----
 pack-objects.h         | 10 ----------
 3 files changed, 13 insertions(+), 26 deletions(-)

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 506061b4c..5439b434c 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -1954,8 +1954,8 @@ static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
 }
 
 /* Protect access to object database */
-#define read_lock()		packing_data_read_lock(&to_pack)
-#define read_unlock()		packing_data_read_unlock(&to_pack)
+#define pack_lock()		packing_data_lock(&to_pack)
+#define pack_unlock()		packing_data_unlock(&to_pack)
 
 /* Protect delta_cache_size */
 static pthread_mutex_t cache_mutex;
@@ -1992,11 +1992,11 @@ unsigned long oe_get_size_slow(struct packing_data *pack,
 	unsigned long used, avail, size;
 
 	if (e->type_ != OBJ_OFS_DELTA && e->type_ != OBJ_REF_DELTA) {
-		read_lock();
+		pack_lock();
 		if (oid_object_info(the_repository, &e->idx.oid, &size) < 0)
 			die(_("unable to get size of %s"),
 			    oid_to_hex(&e->idx.oid));
-		read_unlock();
+		pack_unlock();
 		return size;
 	}
 
@@ -2004,7 +2004,7 @@ unsigned long oe_get_size_slow(struct packing_data *pack,
 	if (!p)
 		BUG("when e->type is a delta, it must belong to a pack");
 
-	read_lock();
+	pack_lock();
 	w_curs = NULL;
 	buf = use_pack(p, &w_curs, e->in_pack_offset, &avail);
 	used = unpack_object_header_buffer(buf, avail, &type, &size);
@@ -2013,7 +2013,7 @@ unsigned long oe_get_size_slow(struct packing_data *pack,
 		    oid_to_hex(&e->idx.oid));
 
 	unuse_pack(&w_curs);
-	read_unlock();
+	pack_unlock();
 	return size;
 }
 
@@ -2075,9 +2075,9 @@ static int try_delta(struct unpacked *trg, struct unpacked *src,
 
 	/* Load data if not already done */
 	if (!trg->data) {
-		read_lock();
+		pack_lock();
 		trg->data = read_object_file(&trg_entry->idx.oid, &type, &sz);
-		read_unlock();
+		pack_unlock();
 		if (!trg->data)
 			die(_("object %s cannot be read"),
 			    oid_to_hex(&trg_entry->idx.oid));
@@ -2088,9 +2088,9 @@ static int try_delta(struct unpacked *trg, struct unpacked *src,
 		*mem_usage += sz;
 	}
 	if (!src->data) {
-		read_lock();
+		pack_lock();
 		src->data = read_object_file(&src_entry->idx.oid, &type, &sz);
-		read_unlock();
+		pack_unlock();
 		if (!src->data) {
 			if (src_entry->preferred_base) {
 				static int warned = 0;
@@ -2336,9 +2336,9 @@ static void find_deltas(struct object_entry **list, unsigned *list_size,
 
 static void try_to_free_from_threads(size_t size)
 {
-	read_lock();
+	pack_lock();
 	release_pack_memory(size);
-	read_unlock();
+	pack_unlock();
 }
 
 static try_to_free_t old_try_to_free_routine;
diff --git a/pack-objects.c b/pack-objects.c
index 3554c43ac..6f32a7ba0 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -148,10 +148,7 @@ void prepare_packing_data(struct packing_data *pdata)
 					     1U << OE_SIZE_BITS);
 	pdata->oe_delta_size_limit = git_env_ulong("GIT_TEST_OE_DELTA_SIZE",
 						   1UL << OE_DELTA_SIZE_BITS);
-#ifndef NO_PTHREADS
-	pthread_mutex_init(&pdata->lock, NULL);
-	init_recursive_mutex(&pdata->read_lock);
-#endif
+	init_recursive_mutex(&pdata->lock);
 }
 
 struct object_entry *packlist_alloc(struct packing_data *pdata,
diff --git a/pack-objects.h b/pack-objects.h
index 0a038e3bc..dc869f26c 100644
--- a/pack-objects.h
+++ b/pack-objects.h
@@ -146,7 +146,6 @@ struct packing_data {
 	struct packed_git **in_pack;
 
 	pthread_mutex_t lock;
-	pthread_mutex_t read_lock;
 
 	/*
 	 * This list contains entries for bases which we know the other side
@@ -175,15 +174,6 @@ static inline void packing_data_unlock(struct packing_data *pdata)
 	pthread_mutex_unlock(&pdata->lock);
 }
 
-static inline void packing_data_read_lock(struct packing_data *pdata)
-{
-	pthread_mutex_lock(&pdata->read_lock);
-}
-static inline void packing_data_read_unlock(struct packing_data *pdata)
-{
-	pthread_mutex_unlock(&pdata->read_lock);
-}
-
 struct object_entry *packlist_alloc(struct packing_data *pdata,
 				    const unsigned char *sha1,
 				    uint32_t index_pos);
-- 
2.20.1.windows.1