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Subject[PATCH v3 3/3] i2c: smbus: switch from loops to memcpy
Date
When copying memory from one buffer to another, instead of open-coding
loops with byte-by-byte copies let's use memcpy() which might be a bit
faster and makes intent more clear.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

---

Changes in v3:
- new patch using memcpy() for moving data around

drivers/i2c/i2c-core-smbus.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c
index 7b4e2270eeda1..bbafdd3b1b114 100644
--- a/drivers/i2c/i2c-core-smbus.c
+++ b/drivers/i2c/i2c-core-smbus.c
@@ -397,8 +397,7 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
}

i2c_smbus_try_get_dmabuf(&msg[0], command);
- for (i = 1; i < msg[0].len; i++)
- msg[0].buf[i] = data->block[i - 1];
+ memcpy(msg[0].buf + 1, data->block, msg[0].len - 1);
}
break;
case I2C_SMBUS_BLOCK_PROC_CALL:
@@ -413,8 +412,7 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,

msg[0].len = data->block[0] + 2;
i2c_smbus_try_get_dmabuf(&msg[0], command);
- for (i = 1; i < msg[0].len; i++)
- msg[0].buf[i] = data->block[i - 1];
+ memcpy(msg[0].buf + 1, data->block, msg[0].len - 1);

msg[1].flags |= I2C_M_RECV_LEN;
msg[1].len = 1; /* block length will be added by
@@ -436,8 +434,7 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
msg[0].len = data->block[0] + 1;

i2c_smbus_try_get_dmabuf(&msg[0], command);
- for (i = 1; i <= data->block[0]; i++)
- msg[0].buf[i] = data->block[i];
+ memcpy(msg[0].buf + 1, data->block + 1, data->block[0]);
}
break;
default:
@@ -489,13 +486,11 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
data->word = get_unaligned_le16(msgbuf1);
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
- for (i = 0; i < data->block[0]; i++)
- data->block[i + 1] = msg[1].buf[i];
+ memcpy(data->block + 1, msg[1].buf, data->block[0]);
break;
case I2C_SMBUS_BLOCK_DATA:
case I2C_SMBUS_BLOCK_PROC_CALL:
- for (i = 0; i < msg[1].buf[0] + 1; i++)
- data->block[i] = msg[1].buf[i];
+ memcpy(data->block, msg[1].buf, msg[1].buf[0] + 1);
break;
}

--
2.24.0.rc1.363.gb1bccd3e3d-goog
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