From d8748eda96b47efea833e2a6ea478bb370654f1d Mon Sep 17 00:00:00 2001 From: Jonathan Bell Date: Wed, 20 Mar 2024 13:00:30 +0000 Subject: [PATCH 0983/1085] drivers: mmc: preallocate a block for SD extension register accesses The Performance Extension register is regularly accessed in a hot path to do write cache flushes. Don't invoke kmalloc/kfree for every access, preallocate a 512B buffer for this purpose. Also remove an unused alloc in sd_enable_cache(). Signed-off-by: Jonathan Bell --- drivers/mmc/core/bus.c | 2 ++ drivers/mmc/core/sd.c | 34 +++++++++++----------------------- include/linux/mmc/card.h | 1 + 3 files changed, 14 insertions(+), 23 deletions(-) --- a/drivers/mmc/core/bus.c +++ b/drivers/mmc/core/bus.c @@ -266,6 +266,8 @@ static void mmc_release_card(struct devi sdio_free_common_cis(card); + kfree(card->ext_reg_buf); + kfree(card->info); kfree(card); --- a/drivers/mmc/core/sd.c +++ b/drivers/mmc/core/sd.c @@ -1026,9 +1026,8 @@ int sd_write_ext_reg(struct mmc_card *ca struct scatterlist sg; u8 *reg_buf; - reg_buf = kzalloc(512, GFP_KERNEL); - if (!reg_buf) - return -ENOMEM; + reg_buf = card->ext_reg_buf; + memset(reg_buf, 0, 512); mrq.cmd = &cmd; mrq.data = &data; @@ -1060,8 +1059,6 @@ int sd_write_ext_reg(struct mmc_card *ca mmc_set_data_timeout(&data, card); mmc_wait_for_req(host, &mrq); - kfree(reg_buf); - /* * Note that, the SD card is allowed to signal busy on DAT0 up to 1s * after the CMD49. Although, let's leave this to be managed by the @@ -1102,9 +1099,7 @@ static int sd_parse_ext_reg_power(struct int err; u8 *reg_buf; - reg_buf = kzalloc(512, GFP_KERNEL); - if (!reg_buf) - return -ENOMEM; + reg_buf = card->ext_reg_buf; /* Read the extension register for power management function. */ err = sd_read_ext_reg(card, fno, page, offset, 512, reg_buf); @@ -1134,7 +1129,6 @@ static int sd_parse_ext_reg_power(struct card->ext_power.offset = offset; out: - kfree(reg_buf); return err; } @@ -1144,9 +1138,7 @@ static int sd_parse_ext_reg_perf(struct int err; u8 *reg_buf; - reg_buf = kzalloc(512, GFP_KERNEL); - if (!reg_buf) - return -ENOMEM; + reg_buf = card->ext_reg_buf; err = sd_read_ext_reg(card, fno, page, offset, 512, reg_buf); if (err) { @@ -1189,7 +1181,6 @@ static int sd_parse_ext_reg_perf(struct card->ext_perf.offset = offset; out: - kfree(reg_buf); return err; } @@ -1260,6 +1251,12 @@ static int sd_read_ext_regs(struct mmc_c if (!gen_info_buf) return -ENOMEM; + card->ext_reg_buf = kzalloc(512, GFP_KERNEL); + if (!card->ext_reg_buf) { + err = -ENOMEM; + goto out; + } + /* * Read 512 bytes of general info, which is found at function number 0, * at page 0 and with no offset. @@ -1326,9 +1323,7 @@ static int sd_flush_cache(struct mmc_hos if (!sd_cache_enabled(host)) return 0; - reg_buf = kzalloc(512, GFP_KERNEL); - if (!reg_buf) - return -ENOMEM; + reg_buf = card->ext_reg_buf; /* * Set Flush Cache at bit 0 in the performance enhancement register at @@ -1364,21 +1359,15 @@ static int sd_flush_cache(struct mmc_hos if (reg_buf[0] & BIT(0)) err = -ETIMEDOUT; out: - kfree(reg_buf); return err; } static int sd_enable_cache(struct mmc_card *card) { - u8 *reg_buf; int err; card->ext_perf.feature_enabled &= ~SD_EXT_PERF_CACHE; - reg_buf = kzalloc(512, GFP_KERNEL); - if (!reg_buf) - return -ENOMEM; - /* * Set Cache Enable at bit 0 in the performance enhancement register at * 260 bytes offset. @@ -1397,7 +1386,6 @@ static int sd_enable_cache(struct mmc_ca card->ext_perf.feature_enabled |= SD_EXT_PERF_CACHE; out: - kfree(reg_buf); return err; } --- a/include/linux/mmc/card.h +++ b/include/linux/mmc/card.h @@ -321,6 +321,7 @@ struct mmc_card { struct sd_switch_caps sw_caps; /* switch (CMD6) caps */ struct sd_ext_reg ext_power; /* SD extension reg for PM */ struct sd_ext_reg ext_perf; /* SD extension reg for PERF */ + u8 *ext_reg_buf; /* 512 byte block for extension register R/W */ unsigned int sdio_funcs; /* number of SDIO functions */ atomic_t sdio_funcs_probed; /* number of probed SDIO funcs */