| Message ID | 1560856182-26072-1-git-send-email-bbiswas@nvidia.com |
|---|---|
| State | Deferred |
| Headers | show |
| Series | [V9] i2c: tegra: remove BUG() macro | expand |
18.06.2019 14:09, Bitan Biswas пишет: > The usage of BUG() macro is generally discouraged in kernel, unless > it's a problem that results in a physical damage or loss of data. > This patch removes unnecessary BUG() macros and replaces the rest > with warning. > > Signed-off-by: Bitan Biswas <bbiswas@nvidia.com> > --- > drivers/i2c/busses/i2c-tegra.c | 47 +++++++++++++++++++++++++++++++++++------- > 1 file changed, 39 insertions(+), 8 deletions(-) Thank you very much! Please keep applying all the advises that were given to you during the reviews in the future patches. I made a quick test and no problems spotted, all warning spots are silent. Reviewed-by: Dmitry Osipenko <digetx@gmail.com> Tested-by: Dmitry Osipenko <digetx@gmail.com>
On 6/18/19 4:29 AM, Dmitry Osipenko wrote: > 18.06.2019 14:09, Bitan Biswas пишет: >> The usage of BUG() macro is generally discouraged in kernel, unless >> it's a problem that results in a physical damage or loss of data. >> This patch removes unnecessary BUG() macros and replaces the rest >> with warning. >> >> Signed-off-by: Bitan Biswas <bbiswas@nvidia.com> >> --- >> drivers/i2c/busses/i2c-tegra.c | 47 +++++++++++++++++++++++++++++++++++------- >> 1 file changed, 39 insertions(+), 8 deletions(-) > > Thank you very much! Please keep applying all the advises that were given to you > during the reviews in the future patches. Thank you Dmitry for the review inputs and patience. I shall try to keep the advices in mind for future reviews. > > I made a quick test and no problems spotted, all warning spots are silent. > > Reviewed-by: Dmitry Osipenko <digetx@gmail.com> > Tested-by: Dmitry Osipenko <digetx@gmail.com> > Also, Thank you for help in testing the patch at your end. -regards, Bitan
On 6/18/19 4:09 AM, Bitan Biswas wrote: > The usage of BUG() macro is generally discouraged in kernel, unless > it's a problem that results in a physical damage or loss of data. > This patch removes unnecessary BUG() macros and replaces the rest > with warning. > > Signed-off-by: Bitan Biswas <bbiswas@nvidia.com> > --- > drivers/i2c/busses/i2c-tegra.c | 47 +++++++++++++++++++++++++++++++++++------- > 1 file changed, 39 insertions(+), 8 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c > index 4dfb4c1..e9ff96d 100644 > --- a/drivers/i2c/busses/i2c-tegra.c > +++ b/drivers/i2c/busses/i2c-tegra.c > @@ -73,6 +73,7 @@ > #define I2C_ERR_NO_ACK BIT(0) > #define I2C_ERR_ARBITRATION_LOST BIT(1) > #define I2C_ERR_UNKNOWN_INTERRUPT BIT(2) > +#define I2C_ERR_RX_BUFFER_OVERFLOW BIT(3) > > #define PACKET_HEADER0_HEADER_SIZE_SHIFT 28 > #define PACKET_HEADER0_PACKET_ID_SHIFT 16 > @@ -489,6 +490,13 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev) > size_t buf_remaining = i2c_dev->msg_buf_remaining; > int words_to_transfer; > > + /* > + * Catch overflow due to message fully sent > + * before the check for RX FIFO availability. > + */ > + if (WARN_ON_ONCE(!(i2c_dev->msg_buf_remaining))) > + return -EINVAL; > + > if (i2c_dev->hw->has_mst_fifo) { > val = i2c_readl(i2c_dev, I2C_MST_FIFO_STATUS); > rx_fifo_avail = (val & I2C_MST_FIFO_STATUS_RX_MASK) >> > @@ -515,7 +523,11 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev) > * prevent overwriting past the end of buf > */ > if (rx_fifo_avail > 0 && buf_remaining > 0) { > - BUG_ON(buf_remaining > 3); > + /* > + * buf_remaining > 3 check not needed as rx_fifo_avail == 0 > + * when (words_to_transfer was > rx_fifo_avail) earlier > + * in this function. > + */ > val = i2c_readl(i2c_dev, I2C_RX_FIFO); > val = cpu_to_le32(val); > memcpy(buf, &val, buf_remaining); > @@ -523,7 +535,10 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev) > rx_fifo_avail--; > } > > - BUG_ON(rx_fifo_avail > 0 && buf_remaining > 0); > + /* RX FIFO must be drained, otherwise it's an Overflow case. */ > + if (WARN_ON_ONCE(rx_fifo_avail)) > + return -EINVAL; > + > i2c_dev->msg_buf_remaining = buf_remaining; > i2c_dev->msg_buf = buf; > > @@ -581,7 +596,11 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev) > * boundary and fault. > */ > if (tx_fifo_avail > 0 && buf_remaining > 0) { > - BUG_ON(buf_remaining > 3); > + /* > + * buf_remaining > 3 check not needed as tx_fifo_avail == 0 > + * when (words_to_transfer was > tx_fifo_avail) earlier > + * in this function for non-zero words_to_transfer. > + */ > memcpy(&val, buf, buf_remaining); > val = le32_to_cpu(val); > > @@ -847,10 +866,15 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) > > if (!i2c_dev->is_curr_dma_xfer) { > if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) { > - if (i2c_dev->msg_buf_remaining) > - tegra_i2c_empty_rx_fifo(i2c_dev); > - else > - BUG(); > + if (tegra_i2c_empty_rx_fifo(i2c_dev)) { > + /* > + * Overflow error condition: message fully sent, > + * with no XFER_COMPLETE interrupt but hardware > + * asks to transfer more. > + */ > + i2c_dev->msg_err |= I2C_ERR_RX_BUFFER_OVERFLOW; > + goto err; > + } > } > > if (!i2c_dev->msg_read && (status & I2C_INT_TX_FIFO_DATA_REQ)) { > @@ -876,7 +900,14 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) > if (status & I2C_INT_PACKET_XFER_COMPLETE) { > if (i2c_dev->is_curr_dma_xfer) > i2c_dev->msg_buf_remaining = 0; > - BUG_ON(i2c_dev->msg_buf_remaining); > + /* > + * Underflow error condition: XFER_COMPLETE before message > + * fully sent. > + */ > + if (WARN_ON_ONCE(i2c_dev->msg_buf_remaining)) { > + i2c_dev->msg_err |= I2C_ERR_UNKNOWN_INTERRUPT; > + goto err; > + } > complete(&i2c_dev->msg_complete); > } > goto done; > Please get back if there are any further comments regarding this patch. -regards, Bitan
On Tuesday 18 June 2019 04:39 PM, Bitan Biswas wrote: > The usage of BUG() macro is generally discouraged in kernel, unless > it's a problem that results in a physical damage or loss of data. > This patch removes unnecessary BUG() macros and replaces the rest > with warning. > > Signed-off-by: Bitan Biswas <bbiswas@nvidia.com> > Acked By: Laxman Dewangan <ldewangan@nvidia.com> Thanks, Laxman
On Tue, Jun 18, 2019 at 04:09:42AM -0700, Bitan Biswas wrote: > The usage of BUG() macro is generally discouraged in kernel, unless > it's a problem that results in a physical damage or loss of data. > This patch removes unnecessary BUG() macros and replaces the rest > with warning. > > Signed-off-by: Bitan Biswas <bbiswas@nvidia.com> > --- > drivers/i2c/busses/i2c-tegra.c | 47 +++++++++++++++++++++++++++++++++++------- > 1 file changed, 39 insertions(+), 8 deletions(-) Acked-by: Thierry Reding <treding@nvidia.com>
On Tue, Jun 18, 2019 at 04:09:42AM -0700, Bitan Biswas wrote: > The usage of BUG() macro is generally discouraged in kernel, unless > it's a problem that results in a physical damage or loss of data. > This patch removes unnecessary BUG() macros and replaces the rest > with warning. > > Signed-off-by: Bitan Biswas <bbiswas@nvidia.com> Applied to for-next, thanks!
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index 4dfb4c1..e9ff96d 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -73,6 +73,7 @@ #define I2C_ERR_NO_ACK BIT(0) #define I2C_ERR_ARBITRATION_LOST BIT(1) #define I2C_ERR_UNKNOWN_INTERRUPT BIT(2) +#define I2C_ERR_RX_BUFFER_OVERFLOW BIT(3) #define PACKET_HEADER0_HEADER_SIZE_SHIFT 28 #define PACKET_HEADER0_PACKET_ID_SHIFT 16 @@ -489,6 +490,13 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev) size_t buf_remaining = i2c_dev->msg_buf_remaining; int words_to_transfer; + /* + * Catch overflow due to message fully sent + * before the check for RX FIFO availability. + */ + if (WARN_ON_ONCE(!(i2c_dev->msg_buf_remaining))) + return -EINVAL; + if (i2c_dev->hw->has_mst_fifo) { val = i2c_readl(i2c_dev, I2C_MST_FIFO_STATUS); rx_fifo_avail = (val & I2C_MST_FIFO_STATUS_RX_MASK) >> @@ -515,7 +523,11 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev) * prevent overwriting past the end of buf */ if (rx_fifo_avail > 0 && buf_remaining > 0) { - BUG_ON(buf_remaining > 3); + /* + * buf_remaining > 3 check not needed as rx_fifo_avail == 0 + * when (words_to_transfer was > rx_fifo_avail) earlier + * in this function. + */ val = i2c_readl(i2c_dev, I2C_RX_FIFO); val = cpu_to_le32(val); memcpy(buf, &val, buf_remaining); @@ -523,7 +535,10 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev) rx_fifo_avail--; } - BUG_ON(rx_fifo_avail > 0 && buf_remaining > 0); + /* RX FIFO must be drained, otherwise it's an Overflow case. */ + if (WARN_ON_ONCE(rx_fifo_avail)) + return -EINVAL; + i2c_dev->msg_buf_remaining = buf_remaining; i2c_dev->msg_buf = buf; @@ -581,7 +596,11 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev) * boundary and fault. */ if (tx_fifo_avail > 0 && buf_remaining > 0) { - BUG_ON(buf_remaining > 3); + /* + * buf_remaining > 3 check not needed as tx_fifo_avail == 0 + * when (words_to_transfer was > tx_fifo_avail) earlier + * in this function for non-zero words_to_transfer. + */ memcpy(&val, buf, buf_remaining); val = le32_to_cpu(val); @@ -847,10 +866,15 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) if (!i2c_dev->is_curr_dma_xfer) { if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) { - if (i2c_dev->msg_buf_remaining) - tegra_i2c_empty_rx_fifo(i2c_dev); - else - BUG(); + if (tegra_i2c_empty_rx_fifo(i2c_dev)) { + /* + * Overflow error condition: message fully sent, + * with no XFER_COMPLETE interrupt but hardware + * asks to transfer more. + */ + i2c_dev->msg_err |= I2C_ERR_RX_BUFFER_OVERFLOW; + goto err; + } } if (!i2c_dev->msg_read && (status & I2C_INT_TX_FIFO_DATA_REQ)) { @@ -876,7 +900,14 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) if (status & I2C_INT_PACKET_XFER_COMPLETE) { if (i2c_dev->is_curr_dma_xfer) i2c_dev->msg_buf_remaining = 0; - BUG_ON(i2c_dev->msg_buf_remaining); + /* + * Underflow error condition: XFER_COMPLETE before message + * fully sent. + */ + if (WARN_ON_ONCE(i2c_dev->msg_buf_remaining)) { + i2c_dev->msg_err |= I2C_ERR_UNKNOWN_INTERRUPT; + goto err; + } complete(&i2c_dev->msg_complete); } goto done;
The usage of BUG() macro is generally discouraged in kernel, unless it's a problem that results in a physical damage or loss of data. This patch removes unnecessary BUG() macros and replaces the rest with warning. Signed-off-by: Bitan Biswas <bbiswas@nvidia.com> --- drivers/i2c/busses/i2c-tegra.c | 47 +++++++++++++++++++++++++++++++++++------- 1 file changed, 39 insertions(+), 8 deletions(-)