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2023-08-22tty: tty_buffer: switch data type to u8Jiri Slaby (SUSE)1-2/+2
There is no reason to have tty_buffer::data typed as unsigned long. Switch to u8, but preserve the ulong alignment using __aligned. This allows for the cast removal from char_buf_ptr(). And for use of struct_size() in the allocation in tty_buffer_alloc() -- in the next patch. Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2023-08-11tty: tty_buffer: make all offsets unsignedJiri Slaby (SUSE)1-5/+5
All these are supposed/expected to be unsigned as they are either counts or offsets. So switch to unsigned for clarity. Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2023-08-11tty: make char_buf_ptr()/flag_buf_ptr()'s offset unsignedJiri Slaby (SUSE)1-2/+2
The offset is meant from the beginning of data, so unsigned. Make it as such for clarity. All struct tty_buffer's members should be unsigned too -- see the next patch. Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2023-08-11tty: use u8 for flagsJiri Slaby (SUSE)1-2/+2
This makes all those 'char's an explicit 'u8'. This is part of the continuing unification of chars and flags to be consistent u8. This approaches tty_port_default_receive_buf(). Note that we do not change signedness as we compile with -funsigned-char. Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]> Cc: William Hubbs <[email protected]> Cc: Chris Brannon <[email protected]> Cc: Kirk Reiser <[email protected]> Cc: Samuel Thibault <[email protected]> Cc: Marcel Holtmann <[email protected]> Cc: Johan Hedberg <[email protected]> Cc: Luiz Augusto von Dentz <[email protected]> Cc: Dmitry Torokhov <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: "David S. Miller" <[email protected]> Cc: Eric Dumazet <[email protected]> Cc: Jakub Kicinski <[email protected]> Cc: Paolo Abeni <[email protected]> Cc: Max Staudt <[email protected]> Cc: Wolfgang Grandegger <[email protected]> Cc: Marc Kleine-Budde <[email protected]> Cc: Dario Binacchi <[email protected]> Cc: Andreas Koensgen <[email protected]> Cc: Jeremy Kerr <[email protected]> Cc: Matt Johnston <[email protected]> Cc: Krzysztof Kozlowski <[email protected]> Cc: Liam Girdwood <[email protected]> Cc: Mark Brown <[email protected]> Cc: Jaroslav Kysela <[email protected]> Cc: Takashi Iwai <[email protected]> Acked-by: Mark Brown <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2023-08-11tty: use u8 for charsJiri Slaby (SUSE)1-2/+2
This makes all those 'unsigned char's an explicit 'u8'. This is part of the continuing unification of chars and flags to be consistent u8. This approaches tty_port_default_receive_buf(). Flags to be next. Signed-off-by: "Jiri Slaby (SUSE)" <[email protected]> Cc: William Hubbs <[email protected]> Cc: Chris Brannon <[email protected]> Cc: Kirk Reiser <[email protected]> Cc: Samuel Thibault <[email protected]> Cc: Dmitry Torokhov <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Max Staudt <[email protected]> Cc: Wolfgang Grandegger <[email protected]> Cc: Marc Kleine-Budde <[email protected]> Cc: "David S. Miller" <[email protected]> Cc: Eric Dumazet <[email protected]> Cc: Jakub Kicinski <[email protected]> Cc: Paolo Abeni <[email protected]> Cc: Dario Binacchi <[email protected]> Cc: Andreas Koensgen <[email protected]> Cc: Jeremy Kerr <[email protected]> Cc: Matt Johnston <[email protected]> Cc: Liam Girdwood <[email protected]> Cc: Mark Brown <[email protected]> Cc: Jaroslav Kysela <[email protected]> Cc: Takashi Iwai <[email protected]> Cc: Peter Ujfalusi <[email protected]> Acked-by: Mark Brown <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2022-11-09tty: Convert tty_buffer flags to boolIlpo Järvinen1-4/+1
The struct tty_buffer has flags which is only used for storing TTYB_NORMAL. There is also a few quite confusing operations for checking the presense of TTYB_NORMAL. Simplify things by converting flags to bool. Despite the name remaining the same, the meaning of "flags" is altered slightly by this change. Previously it referred to flags of the buffer (only TTYB_NORMAL being used as a flag). After this change, flags tell whether the buffer contains/should be allocated with flags array along with character data array. It is much more suitable name that TTYB_NORMAL was for this purpose, thus the name remains. Signed-off-by: Ilpo Järvinen <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2022-06-10tty: Implement lookahead to process XON/XOFF timelyIlpo Järvinen1-0/+1
When tty is not read from, XON/XOFF may get stuck into an intermediate buffer. As those characters are there to do software flow-control, it is not very useful. In the case where neither end reads from ttys, the receiving ends might not be able receive the XOFF characters and just keep sending more data to the opposite direction. This problem is almost guaranteed to occur with DMA which sends data in large chunks. If TTY is slow to process characters, that is, eats less than given amount in receive_buf, invoke lookahead for the rest of the chars to process potential XON/XOFF characters. We need to keep track of how many characters have been processed by the lookahead to avoid processing the flow control char again on the normal path. Bookkeeping occurs parallel on two layers (tty_buffer and n_tty) to avoid passing the lookahead_count through the whole call chain. When a flow-control char is processed, two things must occur: a) it must not be treated as normal char b) if not yet processed, flow-control actions need to be taken The return value of n_tty_receive_char_flow_ctrl() tells caller a), and b) is kept internal to n_tty_receive_char_flow_ctrl(). If characters were previous looked ahead, __receive_buf() makes two calls to the appropriate n_tty_receive_buf_* function. First call is made with lookahead_done=true for the characters that were subject to lookahead earlier and then with lookahead=false for the new characters. Either of the calls might be skipped when it has no characters to handle. Reported-by: Gilles Buloz <[email protected]> Reviewed-by: Andy Shevchenko <[email protected]> Signed-off-by: Ilpo Järvinen <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2021-07-27tty: move tty_buffer definitions to new tty_buffer.hJiri Slaby1-0/+59
tty.h is large enough currently. And I am slowly adding kernel-doc documentation, so it grows to unmaintainable long mess. To avoid this, split tty.h further into tty_buffer.h and move there tty_buffer-related declarations and function prototypes. Note that many of the tty_buffer.c function prototypes reside now in tty_flip.h. But we cannot move struct tty_buffer & friends because: * tty_insert_flip_char() in tty_flip.h needs both struct tty_port and struct tty_buffer defined. * struct tty_port in tty_port.h needs struct tty_buffer defined. So if we moved struct tty_buffer to tty_flip.h too, tty_flip.h would need tty_port.h and that would need tty_flip.h (to have tty_buffer) again. Hence we introduce new header tty_buffer.h here to break this circular dependency. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>