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AxelLinbroonie
AxelLin
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spi: bitbang: Let spi_bitbang_start() take a reference to master
Many drivers that use bitbang library have a leak on probe error paths. This is because once a spi_master_get() call succeeds, we need an additional spi_master_put() call to free the memory. Fix this issue by moving the code taking a reference to master to spi_bitbang_start(), so spi_bitbang_start() will take a reference to master on success. With this change, the caller is responsible for calling spi_bitbang_stop() to decrement the reference and spi_master_put() as counterpart of spi_alloc_master() to prevent a memory leak. So now we have below patten for drivers using bitbang library: probe: spi_alloc_master -> Init reference count to 1 spi_bitbang_start -> Increment reference count remove: spi_bitbang_stop -> Decrement reference count spi_master_put -> Decrement reference count (reference count reaches 0) Fixup all users accordingly. Signed-off-by: Axel Lin <[email protected]> Suggested-by: Uwe Kleine-Koenig <[email protected]> Acked-by: Uwe Kleine-Koenig <[email protected]> Signed-off-by: Mark Brown <[email protected]>
1 parent d0e639c commit 702a487

18 files changed

+33
-26
lines changed

‎drivers/spi/spi-altera.c‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -219,7 +219,7 @@ static int altera_spi_probe(struct platform_device *pdev)
219219
platform_set_drvdata(pdev, hw);
220220

221221
/* setup the state for the bitbang driver */
222-
hw->bitbang.master = spi_master_get(master);
222+
hw->bitbang.master = master;
223223
if (!hw->bitbang.master)
224224
return err;
225225
hw->bitbang.chipselect = altera_spi_chipsel;

‎drivers/spi/spi-ath79.c‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -231,7 +231,7 @@ static int ath79_spi_probe(struct platform_device *pdev)
231231
master->num_chipselect = pdata->num_chipselect;
232232
}
233233

234-
sp->bitbang.master = spi_master_get(master);
234+
sp->bitbang.master = master;
235235
sp->bitbang.chipselect = ath79_spi_chipselect;
236236
sp->bitbang.txrx_word[SPI_MODE_0] = ath79_spi_txrx_mode0;
237237
sp->bitbang.setup_transfer = spi_bitbang_setup_transfer;

‎drivers/spi/spi-au1550.c‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -775,7 +775,7 @@ static int au1550_spi_probe(struct platform_device *pdev)
775775

776776
hw = spi_master_get_devdata(master);
777777

778-
hw->master = spi_master_get(master);
778+
hw->master = master;
779779
hw->pdata = dev_get_platdata(&pdev->dev);
780780
hw->dev = &pdev->dev;
781781

‎drivers/spi/spi-bitbang.c‎

Lines changed: 11 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -414,10 +414,16 @@ static int spi_bitbang_unprepare_hardware(struct spi_master *spi)
414414
* This routine registers the spi_master, which will process requests in a
415415
* dedicated task, keeping IRQs unblocked most of the time. To stop
416416
* processing those requests, call spi_bitbang_stop().
417+
*
418+
* On success, this routine will take a reference to master. The caller is
419+
* responsible for calling spi_bitbang_stop() to decrement the reference and
420+
* spi_master_put() as counterpart of spi_alloc_master() to prevent a memory
421+
* leak.
417422
*/
418423
int spi_bitbang_start(struct spi_bitbang *bitbang)
419424
{
420425
struct spi_master *master = bitbang->master;
426+
int ret;
421427

422428
if (!master || !bitbang->chipselect)
423429
return -EINVAL;
@@ -449,7 +455,11 @@ int spi_bitbang_start(struct spi_bitbang *bitbang)
449455
/* driver may get busy before register() returns, especially
450456
* if someone registered boardinfo for devices
451457
*/
452-
return spi_register_master(master);
458+
ret = spi_register_master(spi_master_get(master));
459+
if (ret)
460+
spi_master_put(master);
461+
462+
return 0;
453463
}
454464
EXPORT_SYMBOL_GPL(spi_bitbang_start);
455465

‎drivers/spi/spi-butterfly.c‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -225,7 +225,7 @@ static void butterfly_attach(struct parport *p)
225225
master->bus_num = 42;
226226
master->num_chipselect = 2;
227227

228-
pp->bitbang.master = spi_master_get(master);
228+
pp->bitbang.master = master;
229229
pp->bitbang.chipselect = butterfly_chipselect;
230230
pp->bitbang.txrx_word[SPI_MODE_0] = butterfly_txrx_word_mode0;
231231

‎drivers/spi/spi-davinci.c‎

Lines changed: 4 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -916,7 +916,7 @@ static int davinci_spi_probe(struct platform_device *pdev)
916916
if (ret)
917917
goto unmap_io;
918918

919-
dspi->bitbang.master = spi_master_get(master);
919+
dspi->bitbang.master = master;
920920
if (dspi->bitbang.master == NULL) {
921921
ret = -ENODEV;
922922
goto irq_free;
@@ -925,7 +925,7 @@ static int davinci_spi_probe(struct platform_device *pdev)
925925
dspi->clk = clk_get(&pdev->dev, NULL);
926926
if (IS_ERR(dspi->clk)) {
927927
ret = -ENODEV;
928-
goto put_master;
928+
goto irq_free;
929929
}
930930
clk_prepare_enable(dspi->clk);
931931

@@ -1015,16 +1015,14 @@ static int davinci_spi_probe(struct platform_device *pdev)
10151015
free_clk:
10161016
clk_disable_unprepare(dspi->clk);
10171017
clk_put(dspi->clk);
1018-
put_master:
1019-
spi_master_put(master);
10201018
irq_free:
10211019
free_irq(dspi->irq, dspi);
10221020
unmap_io:
10231021
iounmap(dspi->base);
10241022
release_region:
10251023
release_mem_region(dspi->pbase, resource_size(r));
10261024
free_master:
1027-
kfree(master);
1025+
spi_master_put(master);
10281026
err:
10291027
return ret;
10301028
}
@@ -1051,11 +1049,11 @@ static int davinci_spi_remove(struct platform_device *pdev)
10511049

10521050
clk_disable_unprepare(dspi->clk);
10531051
clk_put(dspi->clk);
1054-
spi_master_put(master);
10551052
free_irq(dspi->irq, dspi);
10561053
iounmap(dspi->base);
10571054
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
10581055
release_mem_region(dspi->pbase, resource_size(r));
1056+
spi_master_put(master);
10591057

10601058
return 0;
10611059
}

‎drivers/spi/spi-efm32.c‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -347,7 +347,7 @@ static int efm32_spi_probe(struct platform_device *pdev)
347347

348348
ddata = spi_master_get_devdata(master);
349349

350-
ddata->bitbang.master = spi_master_get(master);
350+
ddata->bitbang.master = master;
351351
ddata->bitbang.chipselect = efm32_spi_chipselect;
352352
ddata->bitbang.setup_transfer = efm32_spi_setup_transfer;
353353
ddata->bitbang.txrx_bufs = efm32_spi_txrx_bufs;

‎drivers/spi/spi-fsl-dspi.c‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -450,7 +450,7 @@ static int dspi_probe(struct platform_device *pdev)
450450

451451
dspi = spi_master_get_devdata(master);
452452
dspi->pdev = pdev;
453-
dspi->bitbang.master = spi_master_get(master);
453+
dspi->bitbang.master = master;
454454
dspi->bitbang.chipselect = dspi_chipselect;
455455
dspi->bitbang.setup_transfer = dspi_setup_transfer;
456456
dspi->bitbang.txrx_bufs = dspi_txrx_transfer;

‎drivers/spi/spi-gpio.c‎

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -467,7 +467,7 @@ static int spi_gpio_probe(struct platform_device *pdev)
467467
}
468468
#endif
469469

470-
spi_gpio->bitbang.master = spi_master_get(master);
470+
spi_gpio->bitbang.master = master;
471471
spi_gpio->bitbang.chipselect = spi_gpio_chipselect;
472472

473473
if ((master_flags & (SPI_MASTER_NO_TX | SPI_MASTER_NO_RX)) == 0) {
@@ -486,7 +486,6 @@ static int spi_gpio_probe(struct platform_device *pdev)
486486

487487
status = spi_bitbang_start(&spi_gpio->bitbang);
488488
if (status < 0) {
489-
spi_master_put(spi_gpio->bitbang.master);
490489
gpio_free:
491490
if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
492491
gpio_free(SPI_MISO_GPIO);
@@ -510,13 +509,13 @@ static int spi_gpio_remove(struct platform_device *pdev)
510509

511510
/* stop() unregisters child devices too */
512511
status = spi_bitbang_stop(&spi_gpio->bitbang);
513-
spi_master_put(spi_gpio->bitbang.master);
514512

515513
if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
516514
gpio_free(SPI_MISO_GPIO);
517515
if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
518516
gpio_free(SPI_MOSI_GPIO);
519517
gpio_free(SPI_SCK_GPIO);
518+
spi_master_put(spi_gpio->bitbang.master);
520519

521520
return status;
522521
}

‎drivers/spi/spi-imx.c‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -786,7 +786,7 @@ static int spi_imx_probe(struct platform_device *pdev)
786786
master->num_chipselect = num_cs;
787787

788788
spi_imx = spi_master_get_devdata(master);
789-
spi_imx->bitbang.master = spi_master_get(master);
789+
spi_imx->bitbang.master = master;
790790

791791
for (i = 0; i < master->num_chipselect; i++) {
792792
int cs_gpio = of_get_named_gpio(np, "cs-gpios", i);

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