[dpdk-dev] [PATCH v2] mem: fix cleanup when multi-process is disabled

[Dmitry Kozlyuk]

rte_eal_memory_detach() did not account for cases where multi-process
mode is disabled: --in-memory and --no-shconf. This resulted
in unmapping memory that had not been mapped, which caused errors:

    EAL: Could not unmap memory: No error   (Windows)
    EAL: Cannot munmap(0x1d47f40, 0x7000): Invalid argument  (Linux)

Confusing "No error" was caused by using errno instead of rte_errno
set by rte_mem_unmap().

Skip detaching memory altogether when --in-memory is specified.
Skip unmapping configuration when it's not shared.
Fix and add error handling to produce proper log messages.

Fixes: dfbc61a2f9a6 ("mem: detach memsegs on cleanup")
Cc: Anatoly Burakov <anatoly.burakov at intel.com>

Reported-by: Jie Zhou <jizh at microsoft.com>
Suggested-by: David Marchand <david.marchand at redhat.com>
Signed-off-by: Dmitry Kozlyuk <dmitry.kozliuk at gmail.com>
---
 lib/librte_eal/common/eal_common_memory.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/lib/librte_eal/common/eal_common_memory.c b/lib/librte_eal/common/eal_common_memory.c
index 0e99986d3d..9495170c86 100644
--- a/lib/librte_eal/common/eal_common_memory.c
+++ b/lib/librte_eal/common/eal_common_memory.c
@@ -1006,10 +1006,15 @@ rte_extmem_detach(void *va_addr, size_t len)
 int
 rte_eal_memory_detach(void)
 {
+	const struct internal_config *internal_conf =
+		eal_get_internal_configuration();
 	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
 	size_t page_sz = rte_mem_page_size();
 	unsigned int i;
 
+	if (internal_conf->in_memory == 1)
+		return 0;
+
 	rte_rwlock_write_lock(&mcfg->memory_hotplug_lock);
 
 	/* detach internal memory subsystem data first */
@@ -1032,7 +1037,7 @@ rte_eal_memory_detach(void)
 		if (!msl->external)
 			if (rte_mem_unmap(msl->base_va, msl->len) != 0)
 				RTE_LOG(ERR, EAL, "Could not unmap memory: %s\n",
-						strerror(errno));
+						rte_strerror(rte_errno));
 
 		/*
 		 * we are detaching the fbarray rather than destroying because
@@ -1050,7 +1055,10 @@ rte_eal_memory_detach(void)
 	 * config - we can't zero it out because it might still be referenced
 	 * by other processes.
 	 */
-	rte_mem_unmap(mcfg, RTE_ALIGN(sizeof(*mcfg), page_sz));
+	if (internal_conf->no_shconf == 0)
+		if (rte_mem_unmap(mcfg, RTE_ALIGN(sizeof(*mcfg), page_sz)) != 0)
+			RTE_LOG(ERR, EAL, "Could not unmap shared memory config: %s\n",
+					rte_strerror(rte_errno));
 	rte_eal_get_configuration()->mem_config = NULL;
 
 	return 0;
-- 
2.29.3