nvme: Refactor mmap_registers to add writable parameter

To prepare the stage for the set register feature.

Signed-off-by: Tokunori Ikegami <[email protected]>

nvme.c

@@ -190,7 +190,7 @@ static const char space[51] = {[0 ... 49] = ' ', '\0'};
 static char *output_format_val = "normal";
 int verbose_level;
 
-static void *mmap_registers(nvme_root_t r, struct nvme_dev *dev);
+static void *mmap_registers(nvme_root_t r, struct nvme_dev *dev, bool writable);
 
 const char *nvme_strerror(int errnum)
 {
@@ -984,7 +984,7 @@ static int get_effects_log(int argc, char **argv, struct command *cmd, struct pl
 		__u64 cap;
 
 		r = nvme_scan(NULL);
-		bar = mmap_registers(r, dev);
+		bar = mmap_registers(r, dev, false);
 		nvme_free_tree(r);
 
 		if (bar) {
@@ -5247,14 +5247,18 @@ static int nvme_get_properties(int fd, void **pbar)
 	return err;
 }
 
-static void *mmap_registers(nvme_root_t r, struct nvme_dev *dev)
+static void *mmap_registers(nvme_root_t r, struct nvme_dev *dev, bool writable)
 {
 	nvme_ctrl_t c = NULL;
 	nvme_ns_t n = NULL;
 
 	char path[512];
 	void *membase;
 	int fd;
+	int prot = PROT_READ;
+
+	if (writable)
+		prot |= PROT_WRITE;
 
 	c = nvme_scan_ctrl(r, dev->name);
 	if (c) {
@@ -5272,15 +5276,15 @@ static void *mmap_registers(nvme_root_t r, struct nvme_dev *dev)
 		nvme_free_ns(n);
 	}
 
-	fd = open(path, O_RDONLY);
+	fd = open(path, writable ? O_RDWR : O_RDONLY);
 	if (fd < 0) {
 		if (log_level >= LOG_DEBUG)
 			nvme_show_error("%s did not find a pci resource, open failed %s",
 					dev->name, strerror(errno));
 		return NULL;
 	}
 
-	membase = mmap(NULL, getpagesize(), PROT_READ, MAP_SHARED, fd, 0);
+	membase = mmap(NULL, getpagesize(), prot, MAP_SHARED, fd, 0);
 	if (membase == MAP_FAILED) {
 		if (log_level >= LOG_DEBUG) {
 			fprintf(stderr, "%s failed to map. ", dev->name);
@@ -5332,9 +5336,9 @@ static int show_registers(int argc, char **argv, struct command *cmd, struct plu
 		flags |= VERBOSE;
 
 	r = nvme_scan(NULL);
-	bar = mmap_registers(r, dev);
+	bar = mmap_registers(r, dev, false);
 	if (!bar) {
-		err = nvme_get_properties(dev_fd(dev), &bar);
+		err = nvme_get_properties(dev_fd(dev), &bar, &cfg);
 		if (err)
 			goto free_tree;
 		fabrics = true;