Unverified Commit 9d77522b authored by Christophe JAILLET's avatar Christophe JAILLET Committed by Mark Brown
Browse files

spi: Reorder fields in 'struct spi_transfer' 



Group some variables based on their sizes to reduce hole and avoid padding.
On x86_64, this shrinks the size from 144 to 128 bytes.

Turn 'timestamped' into a bitfield so that it can be easily merged with
some other bifields and move 'error'.

This should have no real impact on memory allocation because 'struct
spi_transfer' is mostly used on stack, but it can save a few cycles
when the structure is initialized or copied.

Signed-off-by: default avatarChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/93a051da85a895bc6003aedfb00a13e1c2fc6338.1676370870.git.christophe.jaillet@wanadoo.fr


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 937ca916

drivers/spi/spi.c

+1 −1
Original line number Diff line number Diff line
@@ -1927,7 +1927,7 @@ void spi_take_timestamp_post(struct spi_controller *ctlr, 
	/* Capture the resolution of the timestamp */

	xfer->ptp_sts_word_post = progress;



	xfer->timestamped = true;

	xfer->timestamped = 1;

}

EXPORT_SYMBOL_GPL(spi_take_timestamp_post);

include/linux/spi/spi.h

+4 −5
Original line number Diff line number Diff line
@@ -1022,6 +1022,9 @@ struct spi_transfer { 
	void		*rx_buf;

	unsigned	len;



#define SPI_TRANS_FAIL_NO_START	BIT(0)

	u16		error;



	dma_addr_t	tx_dma;

	dma_addr_t	rx_dma;

	struct sg_table tx_sg;
@@ -1032,6 +1035,7 @@ struct spi_transfer { 
	unsigned	cs_change:1;

	unsigned	tx_nbits:3;

	unsigned	rx_nbits:3;

	unsigned	timestamped:1;

#define	SPI_NBITS_SINGLE	0x01 /* 1bit transfer */

#define	SPI_NBITS_DUAL		0x02 /* 2bits transfer */

#define	SPI_NBITS_QUAD		0x04 /* 4bits transfer */
@@ -1048,12 +1052,7 @@ struct spi_transfer { 


	struct ptp_system_timestamp *ptp_sts;



	bool		timestamped;



	struct list_head transfer_list;



#define SPI_TRANS_FAIL_NO_START	BIT(0)

	u16		error;

};



/**