fixup! read-cache: run verify_hdr() in background thread

Since picking up a33fc72 (read-cache: force_verify_index_checksum,
2017-04-14), we do not even check the SHA-1 of the index by default
anymore, therefore we no longer need this workaround.

Noticed by Ben Peart.

This reverts commit 480829f.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

read-cache.c

@@ -20,10 +20,6 @@
 #include "split-index.h"
 #include "utf8.h"
 
-#ifndef NO_PTHREADS
-#include <pthread.h>
-#endif
-
 /* Mask for the name length in ce_flags in the on-disk index */
 
 #define CE_NAMEMASK  (0x0fff)
@@ -1538,34 +1534,6 @@ static int verify_hdr(struct cache_header *hdr, unsigned long size)
 	return 0;
 }
 
-#ifndef NO_PTHREADS
-/*
- * Require index file to be larger than this threshold before
- * we bother using a thread to verify the SHA.
- * This value was arbitrarily chosen.
- */
-#define VERIFY_HDR_THRESHOLD	10*1024*1024
-
-struct verify_hdr_thread_data
-{
-	pthread_t thread_id;
-	struct cache_header *hdr;
-	size_t size;
-	int result;
-};
-
-/*
- * A thread proc to run the verify_hdr() computation
- * in a background thread.
- */
-static void *verify_hdr_thread(void *_data)
-{
-	struct verify_hdr_thread_data *p = _data;
-	p->result = verify_hdr(p->hdr, (unsigned long)p->size);
-	return NULL;
-}
-#endif
-
 static int read_index_extension(struct index_state *istate,
 				const char *ext, void *data, unsigned long sz)
 {
@@ -1767,9 +1735,6 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)
 	void *mmap;
 	size_t mmap_size;
 	struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
-#ifndef NO_PTHREADS
-	struct verify_hdr_thread_data verify_hdr_thread_data;
-#endif
 
 	if (istate->initialized)
 		return istate->cache_nr;
@@ -1796,23 +1761,8 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)
 	close(fd);
 
 	hdr = mmap;
-#ifdef NO_PTHREADS
 	if (verify_hdr(hdr, mmap_size) < 0)
 		goto unmap;
-#else
-	if (mmap_size < VERIFY_HDR_THRESHOLD) {
-		if (verify_hdr(hdr, mmap_size) < 0)
-			goto unmap;
-	} else {
-		verify_hdr_thread_data.hdr = hdr;
-		verify_hdr_thread_data.size = mmap_size;
-		verify_hdr_thread_data.result = -1;
-		if (pthread_create(
-				&verify_hdr_thread_data.thread_id, NULL,
-				verify_hdr_thread, &verify_hdr_thread_data))
-			die_errno("unable to start verify_hdr_thread");
-	}
-#endif
 
 	hashcpy(istate->sha1, (const unsigned char *)hdr + mmap_size - 20);
 	istate->version = ntohl(hdr->hdr_version);
@@ -1860,16 +1810,6 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)
 		src_offset += 8;
 		src_offset += extsize;
 	}
-
-#ifndef NO_PTHREADS
-	if (mmap_size >= VERIFY_HDR_THRESHOLD) {
-		if (pthread_join(verify_hdr_thread_data.thread_id, NULL))
-			die_errno("unable to join verify_hdr_thread");
-		if (verify_hdr_thread_data.result < 0)
-			goto unmap;
-	}
-#endif
-
 	munmap(mmap, mmap_size);
 	return istate->cache_nr;