linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Shravan Kumar Ramani <shravankr@nvidia.com>
To: Hans de Goede <hdegoede@redhat.com>,
	Ilpo Jarvinen <ilpo.jarvinen@linux.intel.com>,
	Vadim Pasternak <vadimp@nvidia.com>,
	"David Thompson" <davthompson@nvidia.com>
Cc: Shravan Kumar Ramani <shravankr@nvidia.com>,
	<platform-driver-x86@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>
Subject: [PATCH v3 2/4] platform/mellanox: mlxbf-pmc: Fix signed/unsigned mix-up
Date: Tue, 13 Feb 2024 06:15:26 -0500	[thread overview]
Message-ID: <d8548c70339a29258a906b2b518e5c48f669795c.1707808180.git.shravankr@nvidia.com> (raw)
In-Reply-To: <cover.1707808180.git.shravankr@nvidia.com>

Use unsigned integer types for register values and array indices.
Use %u instead of %d accordingly.

Signed-off-by: Shravan Kumar Ramani <shravankr@nvidia.com>
---
 drivers/platform/mellanox/mlxbf-pmc.c | 129 ++++++++++++++------------
 1 file changed, 68 insertions(+), 61 deletions(-)

diff --git a/drivers/platform/mellanox/mlxbf-pmc.c b/drivers/platform/mellanox/mlxbf-pmc.c
index 86044d1b8fa5..250405bb59a7 100644
--- a/drivers/platform/mellanox/mlxbf-pmc.c
+++ b/drivers/platform/mellanox/mlxbf-pmc.c
@@ -99,8 +99,8 @@
  */
 struct mlxbf_pmc_attribute {
 	struct device_attribute dev_attr;
-	int index;
-	int nr;
+	unsigned int index;
+	unsigned int nr;
 };
 
 /**
@@ -121,7 +121,7 @@ struct mlxbf_pmc_block_info {
 	void __iomem *mmio_base;
 	size_t blk_size;
 	size_t counters;
-	int type;
+	unsigned int type;
 	struct mlxbf_pmc_attribute *attr_counter;
 	struct mlxbf_pmc_attribute *attr_event;
 	struct mlxbf_pmc_attribute attr_event_list;
@@ -169,7 +169,7 @@ struct mlxbf_pmc_context {
  * @evt_name: Name of the event
  */
 struct mlxbf_pmc_events {
-	int evt_num;
+	u32 evt_num;
 	char *evt_name;
 };
 
@@ -956,7 +956,7 @@ static int mlxbf_pmc_write(void __iomem *addr, int command, u64 value)
 }
 
 /* Check if the register offset is within the mapped region for the block */
-static bool mlxbf_pmc_valid_range(int blk_num, u32 offset)
+static bool mlxbf_pmc_valid_range(unsigned int blk_num, u32 offset)
 {
 	if ((offset >= 0) && !(offset % MLXBF_PMC_REG_SIZE) &&
 	    (offset + MLXBF_PMC_REG_SIZE <= pmc->block[blk_num].blk_size))
@@ -966,8 +966,7 @@ static bool mlxbf_pmc_valid_range(int blk_num, u32 offset)
 }
 
 /* Get the event list corresponding to a certain block */
-static const struct mlxbf_pmc_events *mlxbf_pmc_event_list(const char *blk,
-							   int *size)
+static const struct mlxbf_pmc_events *mlxbf_pmc_event_list(const char *blk, size_t *size)
 {
 	const struct mlxbf_pmc_events *events;
 
@@ -1044,7 +1043,8 @@ static const struct mlxbf_pmc_events *mlxbf_pmc_event_list(const char *blk,
 static int mlxbf_pmc_get_event_num(const char *blk, const char *evt)
 {
 	const struct mlxbf_pmc_events *events;
-	int i, size;
+	unsigned int i;
+	size_t size;
 
 	events = mlxbf_pmc_event_list(blk, &size);
 	if (!events)
@@ -1059,10 +1059,11 @@ static int mlxbf_pmc_get_event_num(const char *blk, const char *evt)
 }
 
 /* Get the event number given the name */
-static char *mlxbf_pmc_get_event_name(const char *blk, int evt)
+static char *mlxbf_pmc_get_event_name(const char *blk, u32 evt)
 {
 	const struct mlxbf_pmc_events *events;
-	int i, size;
+	unsigned int i;
+	size_t size;
 
 	events = mlxbf_pmc_event_list(blk, &size);
 	if (!events)
@@ -1077,7 +1078,7 @@ static char *mlxbf_pmc_get_event_name(const char *blk, int evt)
 }
 
 /* Method to enable/disable/reset l3cache counters */
-static int mlxbf_pmc_config_l3_counters(int blk_num, bool enable, bool reset)
+static int mlxbf_pmc_config_l3_counters(unsigned int blk_num, bool enable, bool reset)
 {
 	u32 perfcnt_cfg = 0;
 
@@ -1092,7 +1093,7 @@ static int mlxbf_pmc_config_l3_counters(int blk_num, bool enable, bool reset)
 }
 
 /* Method to handle l3cache counter programming */
-static int mlxbf_pmc_program_l3_counter(int blk_num, u32 cnt_num, u32 evt)
+static int mlxbf_pmc_program_l3_counter(unsigned int blk_num, u32 cnt_num, u32 evt)
 {
 	u32 perfcnt_sel_1 = 0, perfcnt_sel = 0, *wordaddr;
 	void __iomem *pmcaddr;
@@ -1156,7 +1157,7 @@ static int mlxbf_pmc_program_l3_counter(int blk_num, u32 cnt_num, u32 evt)
 }
 
 /* Method to handle crspace counter programming */
-static int mlxbf_pmc_program_crspace_counter(int blk_num, u32 cnt_num, u32 evt)
+static int mlxbf_pmc_program_crspace_counter(unsigned int blk_num, u32 cnt_num, u32 evt)
 {
 	void *addr;
 	u32 word;
@@ -1180,7 +1181,7 @@ static int mlxbf_pmc_program_crspace_counter(int blk_num, u32 cnt_num, u32 evt)
 }
 
 /* Method to clear crspace counter value */
-static int mlxbf_pmc_clear_crspace_counter(int blk_num, u32 cnt_num)
+static int mlxbf_pmc_clear_crspace_counter(unsigned int blk_num, u32 cnt_num)
 {
 	void *addr;
 
@@ -1192,7 +1193,7 @@ static int mlxbf_pmc_clear_crspace_counter(int blk_num, u32 cnt_num)
 }
 
 /* Method to program a counter to monitor an event */
-static int mlxbf_pmc_program_counter(int blk_num, u32 cnt_num, u32 evt, bool is_l3)
+static int mlxbf_pmc_program_counter(unsigned int blk_num, u32 cnt_num, u32 evt, bool is_l3)
 {
 	u64 perfctl, perfevt, perfmon_cfg;
 
@@ -1255,7 +1256,7 @@ static int mlxbf_pmc_program_counter(int blk_num, u32 cnt_num, u32 evt, bool is_
 }
 
 /* Method to handle l3 counter reads */
-static int mlxbf_pmc_read_l3_counter(int blk_num, u32 cnt_num, u64 *result)
+static int mlxbf_pmc_read_l3_counter(unsigned int blk_num, u32 cnt_num, u64 *result)
 {
 	u32 perfcnt_low = 0, perfcnt_high = 0;
 	int status;
@@ -1286,7 +1287,7 @@ static int mlxbf_pmc_read_l3_counter(int blk_num, u32 cnt_num, u64 *result)
 }
 
 /* Method to handle crspace counter reads */
-static int mlxbf_pmc_read_crspace_counter(int blk_num, u32 cnt_num, u64 *result)
+static int mlxbf_pmc_read_crspace_counter(unsigned int blk_num, u32 cnt_num, u64 *result)
 {
 	int status = 0;
 	u32 value;
@@ -1303,7 +1304,7 @@ static int mlxbf_pmc_read_crspace_counter(int blk_num, u32 cnt_num, u64 *result)
 }
 
 /* Method to read the counter value */
-static int mlxbf_pmc_read_counter(int blk_num, u32 cnt_num, bool is_l3, u64 *result)
+static int mlxbf_pmc_read_counter(unsigned int blk_num, u32 cnt_num, bool is_l3, u64 *result)
 {
 	u32 perfcfg_offset, perfval_offset;
 	u64 perfmon_cfg;
@@ -1340,7 +1341,7 @@ static int mlxbf_pmc_read_counter(int blk_num, u32 cnt_num, bool is_l3, u64 *res
 }
 
 /* Method to read L3 block event */
-static int mlxbf_pmc_read_l3_event(int blk_num, u32 cnt_num, u64 *result)
+static int mlxbf_pmc_read_l3_event(unsigned int blk_num, u32 cnt_num, u64 *result)
 {
 	u32 perfcnt_sel = 0, perfcnt_sel_1 = 0, *wordaddr;
 	void __iomem *pmcaddr;
@@ -1392,7 +1393,7 @@ static int mlxbf_pmc_read_l3_event(int blk_num, u32 cnt_num, u64 *result)
 }
 
 /* Method to read crspace block event */
-static int mlxbf_pmc_read_crspace_event(int blk_num, u32 cnt_num, u64 *result)
+static int mlxbf_pmc_read_crspace_event(unsigned int blk_num, u32 cnt_num, u64 *result)
 {
 	u32 word, evt;
 	void *addr;
@@ -1415,7 +1416,7 @@ static int mlxbf_pmc_read_crspace_event(int blk_num, u32 cnt_num, u64 *result)
 }
 
 /* Method to find the event currently being monitored by a counter */
-static int mlxbf_pmc_read_event(int blk_num, u32 cnt_num, bool is_l3, u64 *result)
+static int mlxbf_pmc_read_event(unsigned int blk_num, u32 cnt_num, bool is_l3, u64 *result)
 {
 	u32 perfcfg_offset, perfval_offset;
 	u64 perfmon_cfg, perfevt;
@@ -1454,7 +1455,7 @@ static int mlxbf_pmc_read_event(int blk_num, u32 cnt_num, bool is_l3, u64 *resul
 }
 
 /* Method to read a register */
-static int mlxbf_pmc_read_reg(int blk_num, u32 offset, u64 *result)
+static int mlxbf_pmc_read_reg(unsigned int blk_num, u32 offset, u64 *result)
 {
 	u32 ecc_out;
 
@@ -1475,7 +1476,7 @@ static int mlxbf_pmc_read_reg(int blk_num, u32 offset, u64 *result)
 }
 
 /* Method to write to a register */
-static int mlxbf_pmc_write_reg(int blk_num, u32 offset, u64 data)
+static int mlxbf_pmc_write_reg(unsigned int blk_num, u32 offset, u64 data)
 {
 	if (strstr(pmc->block_name[blk_num], "ecc")) {
 		return mlxbf_pmc_write(pmc->block[blk_num].mmio_base + offset,
@@ -1495,7 +1496,7 @@ static ssize_t mlxbf_pmc_counter_show(struct device *dev,
 {
 	struct mlxbf_pmc_attribute *attr_counter = container_of(
 		attr, struct mlxbf_pmc_attribute, dev_attr);
-	int blk_num, cnt_num, offset;
+	unsigned int blk_num, cnt_num, offset;
 	bool is_l3 = false;
 	u64 value;
 
@@ -1529,14 +1530,15 @@ static ssize_t mlxbf_pmc_counter_store(struct device *dev,
 {
 	struct mlxbf_pmc_attribute *attr_counter = container_of(
 		attr, struct mlxbf_pmc_attribute, dev_attr);
-	int blk_num, cnt_num, offset, err, data;
+	unsigned int blk_num, cnt_num, offset, data;
 	bool is_l3 = false;
 	u64 evt_num;
+	int err;
 
 	blk_num = attr_counter->nr;
 	cnt_num = attr_counter->index;
 
-	err = kstrtoint(buf, 0, &data);
+	err = kstrtouint(buf, 0, &data);
 	if (err < 0)
 		return err;
 
@@ -1565,7 +1567,7 @@ static ssize_t mlxbf_pmc_counter_store(struct device *dev,
 		if (err)
 			return err;
 	} else if (pmc->block[blk_num].type == MLXBF_PMC_TYPE_CRSPACE) {
-		if (sscanf(attr->attr.name, "counter%d", &cnt_num) != 1)
+		if (sscanf(attr->attr.name, "counter%u", &cnt_num) != 1)
 			return -EINVAL;
 		err = mlxbf_pmc_clear_crspace_counter(blk_num, cnt_num);
 	} else
@@ -1580,10 +1582,11 @@ static ssize_t mlxbf_pmc_event_show(struct device *dev,
 {
 	struct mlxbf_pmc_attribute *attr_event = container_of(
 		attr, struct mlxbf_pmc_attribute, dev_attr);
-	int blk_num, cnt_num, err;
+	unsigned int blk_num, cnt_num;
 	bool is_l3 = false;
-	u64 evt_num;
 	char *evt_name;
+	u64 evt_num;
+	int err;
 
 	blk_num = attr_event->nr;
 	cnt_num = attr_event->index;
@@ -1609,8 +1612,9 @@ static ssize_t mlxbf_pmc_event_store(struct device *dev,
 {
 	struct mlxbf_pmc_attribute *attr_event = container_of(
 		attr, struct mlxbf_pmc_attribute, dev_attr);
-	int blk_num, cnt_num, evt_num, err;
+	unsigned int blk_num, cnt_num, evt_num;
 	bool is_l3 = false;
+	int err;
 
 	blk_num = attr_event->nr;
 	cnt_num = attr_event->index;
@@ -1621,7 +1625,7 @@ static ssize_t mlxbf_pmc_event_store(struct device *dev,
 		if (evt_num < 0)
 			return -EINVAL;
 	} else {
-		err = kstrtoint(buf, 0, &evt_num);
+		err = kstrtouint(buf, 0, &evt_num);
 		if (err < 0)
 			return err;
 	}
@@ -1643,9 +1647,11 @@ static ssize_t mlxbf_pmc_event_list_show(struct device *dev,
 {
 	struct mlxbf_pmc_attribute *attr_event_list = container_of(
 		attr, struct mlxbf_pmc_attribute, dev_attr);
-	int blk_num, i, size, len = 0, ret = 0;
 	const struct mlxbf_pmc_events *events;
 	char e_info[MLXBF_PMC_EVENT_INFO_LEN];
+	unsigned int blk_num, i, len = 0;
+	size_t size;
+	int ret = 0;
 
 	blk_num = attr_event_list->nr;
 
@@ -1671,8 +1677,8 @@ static ssize_t mlxbf_pmc_enable_show(struct device *dev,
 {
 	struct mlxbf_pmc_attribute *attr_enable = container_of(
 		attr, struct mlxbf_pmc_attribute, dev_attr);
+	unsigned int blk_num, value;
 	u32 perfcnt_cfg, word;
-	int blk_num, value;
 
 	blk_num = attr_enable->nr;
 
@@ -1692,7 +1698,7 @@ static ssize_t mlxbf_pmc_enable_show(struct device *dev,
 		value = FIELD_GET(MLXBF_PMC_L3C_PERF_CNT_CFG_EN, perfcnt_cfg);
 	}
 
-	return sysfs_emit(buf, "%d\n", value);
+	return sysfs_emit(buf, "%u\n", value);
 }
 
 /* Store function for "enable" sysfs files - only for l3cache & crspace */
@@ -1702,12 +1708,13 @@ static ssize_t mlxbf_pmc_enable_store(struct device *dev,
 {
 	struct mlxbf_pmc_attribute *attr_enable = container_of(
 		attr, struct mlxbf_pmc_attribute, dev_attr);
-	int err, en, blk_num;
+	unsigned int en, blk_num;
 	u32 word;
+	int err;
 
 	blk_num = attr_enable->nr;
 
-	err = kstrtoint(buf, 0, &en);
+	err = kstrtouint(buf, 0, &en);
 	if (err < 0)
 		return err;
 
@@ -1745,10 +1752,10 @@ static ssize_t mlxbf_pmc_enable_store(struct device *dev,
 }
 
 /* Populate attributes for blocks with counters to monitor performance */
-static int mlxbf_pmc_init_perftype_counter(struct device *dev, int blk_num)
+static int mlxbf_pmc_init_perftype_counter(struct device *dev, unsigned int blk_num)
 {
 	struct mlxbf_pmc_attribute *attr;
-	int i = 0, j = 0;
+	unsigned int i = 0, j = 0;
 
 	/* "event_list" sysfs to list events supported by the block */
 	attr = &pmc->block[blk_num].attr_event_list;
@@ -1797,8 +1804,7 @@ static int mlxbf_pmc_init_perftype_counter(struct device *dev, int blk_num)
 		attr->dev_attr.store = mlxbf_pmc_counter_store;
 		attr->index = j;
 		attr->nr = blk_num;
-		attr->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
-							  "counter%d", j);
+		attr->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, "counter%u", j);
 		if (!attr->dev_attr.attr.name)
 			return -ENOMEM;
 		pmc->block[blk_num].block_attr[++i] = &attr->dev_attr.attr;
@@ -1810,8 +1816,7 @@ static int mlxbf_pmc_init_perftype_counter(struct device *dev, int blk_num)
 		attr->dev_attr.store = mlxbf_pmc_event_store;
 		attr->index = j;
 		attr->nr = blk_num;
-		attr->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
-							  "event%d", j);
+		attr->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL, "event%u", j);
 		if (!attr->dev_attr.attr.name)
 			return -ENOMEM;
 		pmc->block[blk_num].block_attr[++i] = &attr->dev_attr.attr;
@@ -1822,30 +1827,31 @@ static int mlxbf_pmc_init_perftype_counter(struct device *dev, int blk_num)
 }
 
 /* Populate attributes for blocks with registers to monitor performance */
-static int mlxbf_pmc_init_perftype_reg(struct device *dev, int blk_num)
+static int mlxbf_pmc_init_perftype_reg(struct device *dev, unsigned int blk_num)
 {
-	struct mlxbf_pmc_attribute *attr;
 	const struct mlxbf_pmc_events *events;
-	int i = 0, j = 0;
+	struct mlxbf_pmc_attribute *attr;
+	unsigned int i = 0;
+	size_t count = 0;
 
-	events = mlxbf_pmc_event_list(pmc->block_name[blk_num], &j);
+	events = mlxbf_pmc_event_list(pmc->block_name[blk_num], &count);
 	if (!events)
 		return -EINVAL;
 
 	pmc->block[blk_num].attr_event = devm_kcalloc(
-		dev, j, sizeof(struct mlxbf_pmc_attribute), GFP_KERNEL);
+		dev, count, sizeof(struct mlxbf_pmc_attribute), GFP_KERNEL);
 	if (!pmc->block[blk_num].attr_event)
 		return -ENOMEM;
 
-	while (j > 0) {
-		--j;
-		attr = &pmc->block[blk_num].attr_event[j];
+	while (count > 0) {
+		--count;
+		attr = &pmc->block[blk_num].attr_event[count];
 		attr->dev_attr.attr.mode = 0644;
 		attr->dev_attr.show = mlxbf_pmc_counter_show;
 		attr->dev_attr.store = mlxbf_pmc_counter_store;
 		attr->nr = blk_num;
 		attr->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
-							  events[j].evt_name);
+							  events[count].evt_name);
 		if (!attr->dev_attr.attr.name)
 			return -ENOMEM;
 		pmc->block[blk_num].block_attr[i] = &attr->dev_attr.attr;
@@ -1857,7 +1863,7 @@ static int mlxbf_pmc_init_perftype_reg(struct device *dev, int blk_num)
 }
 
 /* Helper to create the bfperf sysfs sub-directories and files */
-static int mlxbf_pmc_create_groups(struct device *dev, int blk_num)
+static int mlxbf_pmc_create_groups(struct device *dev, unsigned int blk_num)
 {
 	int err;
 
@@ -1900,18 +1906,19 @@ static bool mlxbf_pmc_guid_match(const guid_t *guid,
 static int mlxbf_pmc_map_counters(struct device *dev)
 {
 	u64 info[MLXBF_PMC_INFO_SZ];
-	int i, tile_num, ret;
+	unsigned int tile_num, i;
+	int ret;
 
 	for (i = 0; i < pmc->total_blocks; ++i) {
 		/* Create sysfs for tiles only if block number <  tile_count */
 		if (strstr(pmc->block_name[i], "tilenet")) {
-			if (sscanf(pmc->block_name[i], "tilenet%d", &tile_num) != 1)
+			if (sscanf(pmc->block_name[i], "tilenet%u", &tile_num) != 1)
 				continue;
 
 			if (tile_num >= pmc->tile_count)
 				continue;
 		} else if (strstr(pmc->block_name[i], "tile")) {
-			if (sscanf(pmc->block_name[i], "tile%d", &tile_num) != 1)
+			if (sscanf(pmc->block_name[i], "tile%u", &tile_num) != 1)
 				continue;
 
 			if (tile_num >= pmc->tile_count)
@@ -1921,9 +1928,9 @@ static int mlxbf_pmc_map_counters(struct device *dev)
 		/* Create sysfs only for enabled MSS blocks */
 		if (strstr(pmc->block_name[i], "mss") &&
 		    pmc->event_set == MLXBF_PMC_EVENT_SET_BF3) {
-			int mss_num;
+			unsigned int mss_num;
 
-			if (sscanf(pmc->block_name[i], "mss%d", &mss_num) != 1)
+			if (sscanf(pmc->block_name[i], "mss%u", &mss_num) != 1)
 				continue;
 
 			if (!((pmc->mss_enable >> mss_num) & 0x1))
@@ -1932,17 +1939,17 @@ static int mlxbf_pmc_map_counters(struct device *dev)
 
 		/* Create sysfs only for enabled LLT blocks */
 		if (strstr(pmc->block_name[i], "llt_miss")) {
-			int llt_num;
+			unsigned int llt_num;
 
-			if (sscanf(pmc->block_name[i], "llt_miss%d", &llt_num) != 1)
+			if (sscanf(pmc->block_name[i], "llt_miss%u", &llt_num) != 1)
 				continue;
 
 			if (!((pmc->llt_enable >> llt_num) & 0x1))
 				continue;
 		} else if (strstr(pmc->block_name[i], "llt")) {
-			int llt_num;
+			unsigned int llt_num;
 
-			if (sscanf(pmc->block_name[i], "llt%d", &llt_num) != 1)
+			if (sscanf(pmc->block_name[i], "llt%u", &llt_num) != 1)
 				continue;
 
 			if (!((pmc->llt_enable >> llt_num) & 0x1))
-- 
2.30.1


  parent reply	other threads:[~2024-02-13 11:15 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-13 11:15 [PATCH v3 0/4] Updates to mlxbf-pmc Shravan Kumar Ramani
2024-02-13 11:15 ` [PATCH v3 1/4] platform/mellanox: mlxbf-pmc: Replace uintN_t with kernel-style types Shravan Kumar Ramani
2024-02-13 11:15 ` Shravan Kumar Ramani [this message]
2024-02-13 11:15 ` [PATCH v3 3/4] platform/mellanox: mlxbf-pmc: Add support for 64-bit counters and cycle count Shravan Kumar Ramani
2024-02-13 11:38   ` Ilpo Järvinen
2024-03-25 11:59   ` Hans de Goede
2024-02-13 11:15 ` [PATCH v3 4/4] platform/mellanox: mlxbf-pmc: Add support for clock_measure performance block Shravan Kumar Ramani

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=d8548c70339a29258a906b2b518e5c48f669795c.1707808180.git.shravankr@nvidia.com \
    --to=shravankr@nvidia.com \
    --cc=davthompson@nvidia.com \
    --cc=hdegoede@redhat.com \
    --cc=ilpo.jarvinen@linux.intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=platform-driver-x86@vger.kernel.org \
    --cc=vadimp@nvidia.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).